Hugh Roe O'Donnell

Hugh Roe O'Donnell (Irish: Aodh Ruadh Ó Domhnaill; 30 October 1572 – 10 September 1602), also known as Red Hugh O'Donnell, was a sixteenth-century Irish clan chief, Lord of Tyrconnell, and senior leader during the rising of the Irish clans against English rule in Ireland known as the Nine Years' War (1593-1602). While Hiram Morgan has contemptuously dubbed Hugh Roe O'Donnell, "a counter-reformation Irish dynast living in the world of Machiavelli's Prince rather than The Cattle-Raid of Cooley", Morgan also concedes that primary sources other than the Elizabethan era English officials who wrote the Calendar of State Papers depict Hugh Roe as a man who genuinely believed in and lived by the traditional code of conduct demanded of an Irish clan chief. For this reason, Hugh Roe remains an iconic figure in the history of Irish nationalism and has recently drawn comparisons in the Spanish news media to both El Cid and William Wallace.

Hugh Roe was born near what is now Lifford, County Donegal into a very ancient and powerful family of the Gaelic nobility of Ireland (flaith). As the son of Sir Hugh O'Donnell, Chief of the Name of Clan O'Donnell, Hugh Roe claimed descent through his paternal line, via the lineage of Conall Gulban (died c. 464 A.D.), from the Pre-Christian High King of Ireland Niall of the Nine Hostages. Through his mother, Iníon Dubh, Hugh Roe was also a descendant of the first 6 Scottish Chiefs of Clan MacDonald of Dunnyveg and from Somerled (d. 1164), the first Lord of the Isles and common ancestor of Clan Donald, Clan MacDougall, Clan MacRory, and Clan MacAlister. Through his additional maternal descent from the marriage between John of Islay, Lord of the Isles and Princess Margaret of Scotland, Hugh Roe was also descended from Scottish Kings Robert the Bruce and Robert II, the first monarch from the House of Stuart. He is sometimes also known as Aodh Ruadh II or Red Hugh II, especially in his native County Donegal.

After his engagement or marriage at the age of 15 to the daughter of Hugh O'Neill of Tyrone and elevation to the position of Tanist (heir apparent) to his father, the Chief of Clan O'Donnell, the English Government was terrified of the potential threat Hugh Roe posed, particularly through his familial links to the many Highland clans of Scotland. The Lord Deputy accordingly arranged for Hugh Roe's kidnapping and four-year imprisonment without trial in Dublin Castle, while covertly backing regime change in Donegal. Following a successful escape shortly before Christmas Day 1591 and the temporary resolution of the lengthy succession dispute within the derbhfine of the O'Donnell dynasty Hugh Roe was inaugurated as Chief of the Name of Clan O'Donnell and Lord of Tír Chonaill at the Rock of Doon in May 1592.

Along with his father-in-law Hugh O'Neill of Tyrone, Hugh Roe led a rising of the Irish clans in the Nine Years' War; motivated firstly by determination to permanently end the religious persecution of the Catholic Church in Ireland by Queen Elizabeth I and her officials. As a further means to achieving that end, O'Donnell and O'Neill also sought the political independence of the Kingdom of Ireland with Archduke Albrecht VII of the House of Habsburg as High King. Hugh Roe led an army of the Irish clans to victory in the Battle of Curlew Pass. After the crushing defeat of Gaelic Ireland at the 1602 Siege of Kinsale, Hugh Roe travelled to Spain to seek badly needed reinforcements from King Philip III.

Unsuccessful, he died at Simancas Castle, was buried, similarly to Christopher Columbus, inside the Chapel of Wonders at the Convent of St. Francis, Valladolid, and was succeeded as Chief by his younger brother Rory O'Donnell. Hugh Roe's premature death made continued resistance by the Irish clans impossible and the Nine Years War was accordingly ended by the Treaty of Mellifont in 1603.

In Valladolid, the recent search by archaeologists for his remains has drawn international media attention. Since 2022, Valladolid has annually reenacted his 1602 funeral procession in period costumes and with an empty casket draped with an Irish tricolour. Red Hugh O'Donnell's birthday is celebrated every year in his birthplace and plans are currently afoot to erect statues of him in both his native town of Lifford and in Simancas, where he died.

Since 1977, the Aodh Ruadh Ó Domhnaill Guild has been advancing his Cause for Canonization as a Saint by the Roman Catholic Church. His current title is Servant of God.

Early life
For the political context of O'Donnell's life see the Tudor conquest of Ireland

Hugh Roe O'Donnell was born on 30 October 1572, as a son to the Chief of the Name and Lord of Tyrconnell, Sir Hugh O'Donnell, and his second wife, Fiona MacDonald, the daughter of the Chief of Clan MacDonald of Dunnyveg. Like other local members of the Gaelic nobility of Ireland, Hugh Roe would have received a Classical Christian education from the Franciscan Friars at Donegal Abbey, whose practice, ever since the beginning of the Reformation in Ireland under King Henry VIII, had been to grant sanctuary to Old English refugees, particularly Roman Catholic priests and religious, who had fled from religious persecution in The Pale. Hugh Roe was also fostered by the Chief of Mac Suibhne Fanad, a gallowglass clan originally from the Scottish Highlands and Islands, who had settled in Donegal and became heavily intermarried with the O'Donnell dynasty's derbhfine. At the Clan's stronghold near Rathmullan, along Lough Swilly, Hugh Roe's foster family would have taught him almost from birth how to live off the land, how to withstand extreme cold and hardship, and how to always follow the code of conduct then demanded of both Scottish and Irish clan chiefs.

In his biography of Rob Roy MacGregor, W.H. Murray described the code of conduct as follows, "The abiding principle is cast up from the records of detail: that right must be seen to be done, no man left destitute, the given word honoured, the strictest honour observed to all who have given implicit trust, and that a guest's confidence in his safety must never be betrayed by his host, or vice versa. There was more of like kind, and each held as its kernel the simple ideal of trust honoured... Breaches of it were abhorred and damned... The ideal was applied 'with discretion'. Its interpretation went deeply into domestic life, but stayed shallow for war and politics."

Hugh Roe had numerous brothers and sisters including Donnell, Rory and Cathbarr. His father, Sir Hugh, was a long-standing ally of the Crown, in an attempt to counterbalance the power of Shane O'Neill and Sir Turlough Luineach O'Neill, the last two Chiefs of Clan O'Neill and Lords of Tír Eoghain. In Sir Hugh's later years, a long-running succession dispute broke out to determine who would succeed him. Although Fiona, better known as Iníon Dubh (Lit. "The Dark Lady", pronounced in Ulster Irish as 'In-neen Doo'), pushed successfully for Red Hugh to become the Tanist of Tyrconnell, Red Hugh's elder half-brother Donnell O'Donnell remained the Crown's favored candidate for the Chiefdom. While there were a number of other claimants to the O'Donnell Chiefdom including Hugh Roe's great uncle Hugh Dubh O'Donnell, the Crown chose to support Donnell as part of their policy of imposing primogeniture succession rather than the Brehon Law policy of Tanistry. Furthermore, Donnell was regarded as the least dangerous potential Clan leader, particularly due to the fact that his mother was an Irish noblewoman. In contrast, as the daughter of the late Scottish Chief of Clan MacDonald of Dunnyveg, Iníon Dubh and her son had ready access to an extremely large and formidable web of interlocking dynastic marriages and mutual kinship obligations involving Clan Chiefs on both sides of the Irish Sea and this fact terrified the highest levels of the English Government, which is why Elizabethan officials often pejoratively referred to Hugh Roe as "Scottish".

According to historian Jane Ohlmeyer, "There is no extant portrait or visual representation of Red Hugh though a contemporary suggested that he was 'above middle height, strong, handsome, well built.'"

In 1584, Hugh Roe saw his first military action as part of Tyrconnell's cavalry, under the command of his father's Marshal and chief advisor, Sir Eoin O'Gallagher, against Clan O'Rourke of West Breifne. To the further terror of the Crown, Donnell O'Donnell was bought off temporarily with the position of High Sheriff of Donegal and Hugh Roe was recognized as lawful Tanist of Tyrconnell.

Personal life
In 1587, at the age of fifteen, Hugh Roe was either married or formally betrothed to Róisín Ní Néill, the daughter of Hugh O'Neill, Earl of Tyrone. This dynastic marriage would further cement a growing alliance between two Irish clans who had traditionally been mortal enemies for centuries.

In 1595, with Hugh O'Neill's consent, Hugh Roe and Róisín, who remained without issue, were separated. According to the Calendar of State Papers, Hugh Roe had hopes of a dynastic marriage alliance with Lady Margarey Burke, the daughter of the Ulick Burke, 3rd Earl of Clanricarde, who had refused to join the Nine Years War. Hugh Roe and Róisín briefly reconciled, but their marriage was eventually annulled and she married Donnell Ballach O'Cahan. In 1600 there was word of another plot, this time for Hugh Roe to marry Lady Joan Fitzgerald, the sister of the Súgán Earl of Desmond. As was the case in the Clanricarde rumours, the Tudor army placed Lady Joan under a sizeable military guard as a precaution against Hugh Roe and his retainers coming to spirit her away. The diversion of so many English troops at the height of the Nine Years War, however, may well have been Hugh Roe's real intention all along.

Imprisonment and escape
In 1587, he was kidnapped by Sir John Perrot, then the English Lord Deputy of Ireland, in an attempt to prevent an alliance between the O'Donnell and O'Neill clans. At Rathmullan, O'Donnell was invited aboard a ship captained by Nicholas Skipper from Dublin to drink sample high quality foreign wines, but was then carried away as part of a pre-planned operation. According to Perrot's 26 September 1587 report to the Queen, the same ship simultaneously abducted the eldest sons of the Chiefs of Clan MacSweeney Fanad, Clan MacSweeney na Doe, and Clan O'Gallagher.

According to the Annals of the Four Masters, "It was a cause of great distress of mind to him to be thus imprisoned; yet it was not for his own sake that he grieved, but for the sake of his country, his land, his friends, and kinsmen, who were in bondage throughout Ireland. He was constantly revolving in his mind the manner in which he might make his escape. This was not an easy matter for him, for he was confined in a closely-secured apartment every night in the castle until sunrise the next day. This castle was surrounded by a wide and very deep ditch, full of water, across which was a wooden bridge, directly opposite the door of the fortress; and within and without the door were stationed a stern party of Englishmen, closely guarding it, so that none might pass in or out without examination."

Meanwhile, in what a Hiberno-Latin history of Donegal Abbey later dubbed one of the first of, "the mad dissensions of the native princes [which] precipitated their downfall", Donnell O'Donnell made an effort to depose as his father as Chief of the Name, backed by the arrival of Royal Irish Army troops dispatched from Dublin Castle under the command of John Connill. Iníon Dubh counteracted this by raising the clans of the Cenel Connaill who remained loyal to her elderly husband, while also hiring large numbers of redshank mercenaries from her native Scotland. She then met her stepson and his followers at the Battle of Doire Leathan on 14 September 1590, while Red Hugh was still a prisoner in Dublin.

According to the Annals of the Four Masters, "The Scots discharged a shower of arrows from their elastic bows, by which they pierced and wounded great numbers, and, among the rest, the son of O'Donnell himself, who, being unable to display prowess or defend himself, was slain at Doire-leathan, on one side of the harbour of Telinn, on the 14th of September. Seldom before that time had his enemies triumphed over him; and the party by whom he was slain had not been by any means his enemies until they encountered on this occasion; and although this Donnell was not the rightful heir of his father, it would have been no disgrace to Tirconnell to have elected him as its chief, had he been permitted to attain to that dignity. In this conflict were slain along with Donnell the three sons of Owen, son of Mulmurry, son of Donough above mentioned, together with two hundred others, around Donnell."

Despite the defeat of their plans for regime change, Humphrey Willis, Sir Donnell's replacement as the Sheriff of Donegal, Captain John Connill, and their men did not retreat from Tyrconnell, but instead began raiding and pillaging, extorting local inhabitants to give both them supplies and protection money. At one point Connill captured Sir Hugh O'Donnell, but he was freed by a cousin Niall Garve O'Donnell.

According to a 1617 history of Donegal Abbey written in Louvain, "The entire principality was plundered by Fitzwilliam's sheriff's and captains, to whom he sold the appointments. The more remote the shire and the more Irish, the larger the sum paid. One Boen, for example, obtained a captaincy for a bribe of two gold chains, which he gave to the sordid deputy's wife; and another, named Willis, got a similar preferment for sixty pounds. These unscrupulous marauders pillaged the country and held the heads of families in their grasp until ransomed, some for two hundred, and others for three hundred cows; and when the cattle were not forthcoming they tortured their prisoners by frying the soles of their feet in seething butter and brimstone. As for our friars, they were obliged to betake themselves, with muniments and altar-plate, to the fastness of the mountains, to avoid Willis and his brigands; who a few months before Hugh Roe's return, swooped down upon Donegal in the dead of night, killing thirty of its inhabitants, and occupying the monastery as a garrison."

After having been in English captivity for three years and three months inside Dublin Castle, O'Donnell escaped in 1590, in the company of fellow Ulster hostages Daniel MacSweeney Gorm and Hugh O'Gallagher.

According to the Annals of the Four Masters, "At the very end of winter, as Hugh and a party of his companions were together, in the beginning of the night, before they were put into the close cells in which they used to be every night, they took with them a very long rope to a window which was near them, and by means of the rope they let themselves down, and alighted upon the bridge that was outside the door of the fortress. There was a thick iron chain fastened to this door, by which one closed it when required; through this chain they drove a strong handful of a piece of timber, and thus fastened the door on the outside, so that they could not be immediately pursued from the fortress. There was a youth of Hugh's faithful people outside awaiting their escape, and he met them on coming out."

O'Donnell made it as far as the County Wicklow and the territory of Felim O'Toole, Chief of Clan O'Toole, who had previously visited Dublin Castle to help plan Hugh Roe's escape. Under pressure from the derbhfine of his clan, who feared the consequences of aiding so high profile of a fugitive, O'Toole agreed to surrender Hugh Roe to the posse of English soldiers who were already en route. According to Philip O'Sullivan Beare, however, word was secretly dispatched to Felim O'Toole's brother in law Fiach McHugh O'Byrne, Chief of the Name of Clann Uí Bhroin (Clan O'Byrne) and Lord of Ranelagh, that Hugh Roe needed to be urgently rescued. O'Byrne and his clansmen immediately set out from Glenmalure for that very purpose, but their inability to cross a flooded river prevented them from reaching Clan O'Toole's stronghold quickly enough. Hugh Roe was accordingly recaptured by the English posse and was returned to Dublin Castle in chains.

According to the Annals of the Four Masters, after his return to Dublin Castle, "When Hugh arrived in Dublin, the Council were rejoiced at his return to them; for they made nothing or light of all the other prisoners and hostages that had escaped from them. He was again put into the same prison, and iron fetters were put upon him as tightly as possible; and they watched and guarded him as well as they could. His escape, thus attempted, and his recapture, became known throughout the land of Ireland, at which tidings a great gloom came over the Irish people."

Hugh O'Donnell made a second escape attempt shortly before Christmas Day 1591, joined by Hugh O'Neill's cousins Art and Henry O'Neill, the sons of Shane O'Neill, and with the assistance of local Irish clan chief Fiach McHugh O'Byrne, and an Old English Recusant named Edward Eustace, who carried four horses at the ready. According to Philip O'Sullivan Beare, "On the appointed night, Roe procured a file with which he cut the fastenings of his, Henry's, and Art's chains. He also procured a very long silken rope by which to let themselves down from the top of the high castle. In the early part of a stormy night, they tied one end of the rope to the privy and first Henry clutching the rope with his hands and between his legs, descended down the privy sewer, and without waiting for his companions, took the road for Ulster and escaped safely. Roe followed and waited for Art. Art in sliding down the rope too quickly was badly hurt by a stone which accidentally fell from the sewer and was scarcely able to pick himself up. The lad Edward, who had promised the horses, had four fleet steeds saddled in stable the three previous days, but on this day they had been taken away by a friend without his knowledge. The guide sent by Fiach [an emissary named Turlough Roe O'Hagan] was waiting near the castle, and during the night and the following day conducted Roe and Art through bye-ways and lonely places, lest they be caught. It was winter time, a few days before the Feast of Our Lord's Nativity, and the ground was covered with deep snow."

As O'Donnell had not expected the journey to be on foot, he had not worn proper shoes, which were soon worn out during their efforts to reach the stronghold of Fiach McHugh O'Byrne at Glenmalure. While Art O'Neill had much better footwear, he was weakened both by the lack of food and drink, as well as by the injury he had received from the falling stone during their escape. For this reason, O'Hagan went on ahead, while O'Donnell and O'Neill remained in hiding inside a cave along the slopes of Conavalla, in the Wicklow Mountains. O'Donnell managed to survive by eating leaves, roots, and bark, but despite his pleas, Art O'Neill could not eat. By the time O'Byrne's clansmen arrived to rescue them, Art O'Neill was dying of hypothermia and expired before their eyes. O'Donnell was taken to Glenmalure where he recovered.

As was often the case in Elizabethan era prisons, it is very likely, according to Hiram Morgan, that bribery played a part in their escape, and that even the Lord Deputy William FitzWilliam, may have been complicit. With this in mind, an outraged Queen Elizabeth I wrote to Lord Deputy Thomas Burgh in May 1592 and decreed, "O'Donnell escaped by the practice of money bestowed on somebody. Call to you the Chancellor, Chief Justice Gardiner, and the Treasurer, and inquire who they are that have been touched by it." According to a 1614 history of Donegal Abbey, Hugh Roe's father-in-law, Hugh O'Neill, did in fact bribe Lord Deputy Fitzwilliam with £1,000 to secretly assist, "in the flight of his illustrious captive." In 1600, a deposition by Eoin MacHugh MacNeill Mór O'Neill implicated Richard Weston, one of O'Neill's allies, in bringing O'Donnell the silken rope that aided his escape.

Becoming Chief of the Name
Upon his return to his father's castle at Ballyshannon, Hugh Roe's big toes were amputated by Tyrconnell surgeons due to frostbite. Hugh Roe's father summoned the clan to a gathering in the Gap of Barnesmore and abdicated in his son's favour. Iníon Dubh temporarily bought off the one remaining rival claimant, Niall Garbh Ó Domhnaill, Chief of the Clann Dalaigh branch of the O'Donnell derbhfine and who, with similar duties to a Highland Tacksman, was based in east Tyrconnell, with a dynastic marriage to her stepdaughter Nuala. Red Hugh O'Donnell accordingly received the uncontested leadership of the Clan O'Donnell. At the "Rock of Doon", near Termon, he was acclaimed as, "The O'Donnell", Chief of the Name and Lord of Tyrconnell on 3 May 1592. After Hugh Dubh's abdication, according to O'Sullivan Beare, "he himself, after the manner of Irish Chiefs, devoted the seven years which he lived after this, to prayer and meditation on holy things." Sir Hugh O'Donnell spent those years living among the Franciscans at Donegal Abbey and doing penance for his sins, of which he most deeply regretted his role in the 1588 massacre of sailors from the Spanish Armada, who had been shipwrecked off the coast of Inishowen, and in obedience to orders from Lord Deputy Fitzwilliam. Upon his death c. 1600, the remains of Sir Hugh O'Donnell were first clothed in the habit of a Franciscan monk and then buried underneath the Chapel of Donegal Abbey.

While describing how The O'Donnell was inaugurated on 3 May 1592, Timothy T. O'Donnell has written, "The inauguration of the O'Donnell as King of Tyrconnell was both civil and religious in nature. The ceremony took place on the great Rock of Doon which is one mile west of Kilmacrenan, from which one is give a breathtaking view of the surrounding country. It began with the religious rites in the church of the nearby monastery and holy well singing Psalms and hymns in honor of Christ and St. Columba for the success of the Prince's sovereignty. Standing on the Rock surrounded by nobles and his clansmen, the Prince received an oath in which he promised to preserve the Church and the laws of the land. The Prince also vowed to deliver the succession of the realm peacefully to his Tanist (his successor). O'Ferghil, the hereditary warden and abbot of Kilmacrenan, performed the religious ceremony of the inauguration of The O'Donnell. O'Gallagher was the Prince's Marshal and O'Clery was the Ollamh, or scholarly lawyer who presented to him the book containing the laws and customs of the land and the straight white wand symbolizing the moral rectitude demanded of his judgments and rule." Then, in honour of the Holy Trinity, Hugh would have surveyed his Clan lands as he walked three times sunwise around the peak of Rock of Doon, after which all the Irish clans present loudly acclaimed him as "O'Donnell! O'Donnell! O'Donnell!"

Immediately after his coronation as Chief, Hugh Roe O'Donnell raised the Cenel Connaill and surrounded Captain Humphrey Willis, the Sheriff of County Donegal, and the two companies of English soldiers with which he had been extorting tribute from their barracks inside Donegal Abbey, into which Willis has reported driven a herd of more than three hundred stolen head of cattle.

According to the traditions of local Gaelic warfare, the 6th-century psalter known as the Cathach of St. Columba was believed to guarantee victory upon the battlefield to the Irish clans of the Cenel Connail. Before a battle, like that about to take place at Donegal Abbey, it was customary for a monk or holy man (usually from the Clan McGroarty, and who was in a state of grace) to wear the Cathach and the cumdach ("book shrine"), around his neck and walk three times sunwise around the warriors of Tyrconnell.

According to the 1614 history of Donegal Abbey, "Sensible of the straits to which he was reduced, Willis threatened to fire the buildings; but the young Prince, anxious to preserve the sacred edifice, suffered him and his people to depart unharmed." The peace terms reportedly stipulated, though, that Willis and his soldiers were forbidden to take any stolen cattle or other looted property with them as they crossed into Connaught.

According to Philip O'Sullivan Beare, "Being surrounded there [Willis] surrendered to Roe by whom he was dismissed in safety with an injunction to remember his words, that the Queen and her officers were dealing unjustly with the Irish; that the Catholic religion was contaminated by impiety; that holy bishops and priests were inhumanely and barbarously tortured; that Catholic noblemen were cruelly imprisoned and ruined; that wrong was deemed right; that he himself had been treacherously and perfidiously kidnapped; and that for these reasons he would neither give tribute or allegiance to the English."

The 1614 history of Donegal Abbey continues, "The friars returned immediately afterwards; and O'Donnell, for such was now his name and title, seeing the poverty of the district - swept so bare by the English, offered to support the community and repair the buildings out of his own revenues, if we would forgo our usage of questing from door to door. The proposal, however, was declined; and the people, their scant means notwithstanding, shared their last morsel with us."

The Nine Years War
He successfully led two expeditions against Turlough Luineach O'Neill in 1593, to force Turlough O'Neill to abdicate his chieftainship in favour of Hugh O'Neill. At this point, O'Neill did not join O'Donnell in open war but secretly backed him to enhance their bargaining power with the English. O'Neill by now was also communicating with Philip II of Spain in a quest for military aid.

Declaring open rebellion against the English the following year, O'Donnell received fealty within Connacht from counties Sligo to Leitrim by 1595, and O'Donnell personally re-instated the Chiefdom of Clan MacWilliam Íochdar of the completely Gaelicised House of Burgh in County Mayo, which had been abolished under the policy of surrender and regrant. Instead, however, of allowing Clan a Burc to summon a gathering at which the nobles and commons would debate and then choose one of the derbhfine of the last chief to lead them, O'Donnell instead chose to appoint his ally Tiobóid mac Walter Ciotach Búrca as Chief of the Name. By also passing over the claim of her son Tiobóid na Long Búrca of the Chiefdom, O'Donnell made himself a permanent and very dangerous enemy out of his mother's former ally; the famous pirate queen Grace O'Malley. The latter was swift to retaliate by launching an English-backed regime change war, in which she fought against Hugh Roe in order to wrest the White Wand of the Chiefdom away from Tiobóid Mac Walter Ciotach and give it to her son. In this same year, Hugh O'Neill, Earl of Tyrone, abandoned negotiation with the English by raising his clan and launching the successful Assault on the Blackwater Fort. In 1596, the combined forces of O'Donnell and O'Neill defeated an English army under Sir Henry Bagenal at the Battle of Clontibret.

Their greatest victory came two years later however at Battle of the Yellow Ford on the Blackwater River near the southern border of Tír Eoghain in August 1598. At this battle, the Irish annihilated an English force marching to relieve the siege of Blackwater Fort, five miles northwest of the Elizabethan Army's government's garrison town of Armagh. Later that year, O'Donnell purchased Ballymote Castle from the Chief of Clan MacDonagh and subsequently made it his primary residence.

O'Neill then went south to secure the allegiance of Irish clans in Munster, without much success. Meanwhile, O'Donnell claimed sovereignty over the Irish clans and Old English town-dwellers of Connacht and, as is traditional in the warfare of Gaelic Ireland, Hugh Roe subjected those among both ethnicities who sided with the Queen to both cattle raiding and arson. As part of his war against the Pro-English Ulick Burke, 3rd Earl of Clanricarde, Hugh Roe besieged the Earl's town of Athenry. During the 16th century, the usual laws and customs of war permitted up to three days of sacking after the fall of a city, but, according to his biographer Lughaidh Ó Cléirigh, after the fall of Athenry, Hugh Roe allowed his troops to sack the city for only one day.

Upon being refused entry to Galway City by the Old English and Royalist city government, Hugh Roe burned the suburbs:

"'... he sent forth swift-moving marauding parties through the district of Caladh, and the upper part of the territory; and they carried off many herds of cows and other preys to O'Donnell, to the town of Athenry; and though the warders of the town attempted to defend it, the effort was of no avail to them, for O'Donnell's people applied fires and flames to the strongly-closed gates of the town, and carried to them great ladders, and, placing them against the walls, they recte, some of them ascended to the parapets of the wall. They then leaped from the parapets, and gained the streets of the town, and opened the gates for those who were outside. They all then proceeded to demolish the storehouses and the strong habitations; and they carried away all the goods and valuables that were in them. They remained that night in the town. It was not easy to enumerate or reckon the quantities of copper, iron, clothes, and habiliments, which they carried away from the town on the following day. From the same town he sent forth marauding parties to plunder Clanrickard, on both sides of the river; and these marauders totally plundered and ravaged the tract of country from Leathrath to Magh-Seanchomhladh. The remaining part of his army burned and ravaged the territory, from the town of Athenry and Rath-Goirrgin Westwards to Rinn-Mil and Meadhraige, and to the gates of Galway, and burned Teagh-Brighde, at the military gate of Galway'."

Despite these and other assaults, however, O'Donnell was unable to persuade local Royalist Old English and Irish clans to change their allegiance.

However, in the next two years, O'Donnell and O'Neill were hard-pressed with the deployment of thousands more English troops in the country. The O'Donnell also ambushed and slew an English expedition led by Sir Conyers Clifford to relieve the siege of the pro-English Clan O'Connor Sligo at Colloney Castle at the Battle of Curlew Pass in 1599. After Sir Conyers' severed head was shown to the Castle's defenders, they surrendered. But O'Donnell and O'Neill's positions were increasingly defensive.

The Siege of Donegal
Even worse for O'Donnell was a regime change war launched by his kinsman (cousin and brother-in-law), Niall Garbh Ó Domhnaill, based on Sir Henry Docwra's agreement to support his claim to the O'Donnell Chiefdom. Niall Garbh's brothers and an estimated one thousand Clan O'Donnell warriors also joined his efforts to wrest the White wand away from Hugh Roe with the support of the Crown.

Niall Garbh's support, however, allowed the Tudor navy under Sir Henry Docwra and Humphrey Willis to land a seaborne force at Derry into the heart of Tyrconnell and also capture Clan O'Donnell's traditional stronghold, which Hugh Roe had entrusted to Niall Garbh, in the Battle of Lifford.

In response, Hugh Roe's half-sister, Nuala O'Donnell, immediately separated from her husband, joined the court of her half-brother, and brought her children with her. Meanwhile, Hugh Roe was at the head of his army in Thomond when he received word of Niall Garbh's uprising. O'Donnell and his followers immediately hurried back to Tyrconnell to retake control of his native district.

According to the Elizabeth era English officials who wrote the Calendar of State Papers, Hugh Roe was so outraged by his brother in law's defection, that he ordered mass hangings of Niall Garbh's followers and personally killed Niall Garbh's four-year-old son (and his own nephew) by bashing his brains out against a post. Allegations about Hugh Roe's murder of her child, however, do not explain why Nuala O'Donnell did not similarly change her allegiance, as the code of conduct would have demanded. It is very well-documented, in fact, that Nuala remained loyal to her half-brother and his siblings, for which she has been praised in Irish bardic poetry. Furthermore, the Hiberno-Latin historians from Donegal Abbey did not consider Niall Garbh's efforts to seize the Chiefdom to be justified under the traditional code of conduct and according denounced Niall Garbh as, "a traitor" and "a perfidious wretch."

Philip O'Sullivan Beare, on the other hand, was more nuanced in his assessment, "Garve was a man of great spirit and daring, skilled in military matters and had many of the men of Tyrconnell on his side, fortified by whose aid and valour he did not decline a fight with the Catholics in the open. However, he always retained the Catholic Faith and kept aloof from heretical rites."

On 10 August 1601, the monks of Donegal Abbey carefully removed all sacred objects and fled by ship from their enclosure shortly before Niall Garbh O'Donnell seized control of the monastery buildings and fortified them with earthenworks, which he built with the assistance of Tudor navy engineers, who also helped him to repair the dilapidated buildings of Donegal Castle for the expected siege by Hugh Roe's forces.

According to the history of Donegal Abbey, "Meanwhile, O'Donnell arrived, pitched his camp at Carrig, within two thousand paces of Donegal, and resolved to give Nial and his followers no rest, night or day, as long as they remained within the desecrated walls. A series of hand to hand conflicts, in which Nial's people suffered severely, ensued; and in the course of a fortnight many of the revolted Irish, repenting their treason, deserted in twos and threes to our Prince's camp."

According to Philip O'Sullivan Beare, "There was frequent and sharp fighting between the Catholics and royalists round Derry and Lifford. We may mention a cavalry fight in which the royalists being routed, Manus, brother of O'Donnell's, would have run through with his spear Garve as he retired, had not the blow been parried Owen O'Gallagher, surnamed Oge, a comrade of Manus, but actuated by his devotion and affection for Niall's family who were their lords. Cornelius O'Gallagher was differently disposed to this family, and is said to have persuaded Garve to go over to the English, and who wounded Manus at Monin, near Lifford, where a cavalry fight was suddenly sprung on both parties and Manus charging into five Irish royalists was struck in the right side by a spear thrust from Grave and being surrounded was struck by Cornelius under the shoulder. However, the points of the spears did not penetrate the cuirass, but nevertheless reached the body of Manus. Roderick coming to his brother's aid aimed his spear at Garve's breast. Garve tightening the reins raised his horse's head which received Roderick's blow by which the horse fell dead under Garve; but he, lifted up by his men, returned to Lifford when O'Donnell was coming up with the foot. Manus died of his wounds after fifteen days and shortly after Cornelius was captured by O'Donnell and hanged."

Sir Henry Docwra was reportedly delighted by Niall Garbh's role in the slaying of Hugh Roe's brother Manus. Niall Garbh had previously shown signs of wanting to call off the uprising and make peace with his cousin and brother in law, but Docwra knew that the death of Manus O'Donnell represented such an insult under the traditional honour code as to make a peaceful solution far more difficult if not outright impossible. Even so, Niall Garbh is still said to have tried to arrange one.

According to the history of Donegal Abbey, "Cooped up in the monasteries, so vigilantly watched by O'Donnell that they could not come out into the open country to lift preys, Nial's people began to mutiny; when on the night of Michaelmas, the powder stored in the monastery of Donegal took fire, whether accidentally or by the special interposition of Heaven I know not, and exploded with a terrible crash, that was heard far out at sea, may, scared the wild deer in the coverts of Barnesmore. Oh, the appalling spectacle! Hundreds of the besieged were blown to atoms; others, among the rest Nial's own brother, were crushed to death by masses of the rent masonry; and all that night, while the woodwork blazed like a red volcano, in whose glare friend and foe were distinctly visible to each other, O'Donnell's swordsmen pressed the survivors back across the trenches into the flames, where upwards of a thousand of them perished miserably. Nor should it be forgotten that a ship, laden with munitions for the besieged, ran in a rock, and went to pieces that very night, just as she was entering the bay of Donegal. Next morning Nial proceeded unobserved by O'Donnell's troops, along the strand to Magherabeg, and returned, under cover of the guns of the English war vessel, with the soldiers he had left in that place, determined to maintain himself to the last among the smoldering ruins. O'Donnell immediately shifted his camp nearer to Donegal, and continued the siege till October; when, being informed that the Spaniards had landed at Kinsale, he struck his tents and marched to their assistance."

Kinsale
The Spanish General Juan del Águila finally landed and was besieged by the English Army inside the walled city of Kinsale – at virtually the opposite end of Ireland from the Northern clans - in September 1601. Seeking to break the siege and rescue their Spanish allies, O'Donnell led his warriors in a hard march during the extremely bitter winter conditions of 1601, often covering over 40 miles a day, to join Hugh O'Neill at his warriors at Kinsale, arriving in early December 1601.

En route, true to his family arms and Constantinian motto In Hoc Signo Vinces and in anticipation of the battle to come, Red Hugh visited and venerated the relic of the True Cross, the Holy rood, on the Feast of St. Andrew, on 30 November 1601 at Holy Cross Abbey, and removed a portion of it.

From there he dispatched an expedition to Ardfert in County Kerry, to win a quick victory and successfully recover the territory of his ally, James Fitzmaurice, Lord of Kerry, who had lost it and his 9-year-old son, to Sir Charles Wilmot. Red Hugh also left some O'Donnell clansmen behind in Ardfert to defend Clanmaurice country, notably his first cousin and nephew, Domhnall Óg, son of his late half-brother and rival for the succession, Sir Domhnall O'Donnell, and who appears in the FitzMaurice pardon of 16 July 1604.

At the Battle of Kinsale on (according to the Julian Calendar then used in Elizabethan era England: 24 December 1601) Gregorian Calendar: 5/6 January 1602, the combined forces of Irish clans were defeated by Sir Charles Blount, Lord Mountjoy. O'Donnell and his clansmen arrived as the defeated Irish clans were withdrawing with heavy losses from the field and he tried in vain to rally them, but in the end, Clan O'Donnell escaped the battle without serious losses. The defeat at Kinsale, for which O'Donnell unjustly blamed himself, would prove every bit as devastating for Gaelic Ireland as the Battle of Culloden would be for their fellow Gaels in Scotland in 1746.

Juan del Aguila then surrendered Kinsale on terms and departed with his forces for Spain. Based almost certainly upon Jesuit lay brother and future Irish Catholic Martyr Dominic Collins' tactical assessments, Irish Jesuit priest and Spanish Royal Army military chaplain Fr. James Archer immediately engaged in recrimination. He accused Spanish expeditionary force commander Juan del Águila of cowardice, vacillation, and dereliction of duty for both refusing to heed the advice of the local Irish clans and refusing to sally forth and meet his Ulster allies at the critical point. Archer concluded, "[He] has the reputation in other parts of being a brave soldier, but [in Ireland he was] cowardly and timorous."

Meanwhile, as the defeated Irish clans gathered in a conference at Inishannon, an outraged and heartbroken Hugh Roe O'Donnell announced his plans to travel to Spain to seek further reinforcements from King Philip III. This announcement devastated his supporters, who suspected, despite O'Donnell's vow he would return before the next spring with twenty thousand more Spanish Royal Army soldiers, that they would never see him again.

Exile in Spain
After the Irish defeat at Kinsale, O'Donnell left Ireland on 6 January 1602 and sailed to Corunna in Galicia, Spain, where many other Irish clan chiefs were already arriving as refugees with their families. There he was received with great honours by the Governor of Galicia and the Lord Archbishop of Santiago de Compostela, where an Irish College was founded. He was also taken to "visit the Tower of Brigantiums, where according to bardic legends the sons of Milesius left to the Isle of Destiny".

O'Donnell then travelled to Valladolid to ask further assistance from King Philip III. When he arrived in the Royal presence, O'Donnell knelt before the King and vowed not to rise until three requests were granted, "The first is that you send a Spanish Army with me to Ireland. The second is that once you rule Ireland, I will be the most powerful Irish noble there. The third is that you protect the rights of the O'Donnells forever." The King immediately agreed and ordered O'Donnell to rise.

According to Irish historian John McCavitt, "He made sure to position himself with a recognisable aristocratic rank while he also emphasised the Irish's sacrifice for Spain in turning down the chance for peace with England in the hope a further Spanish invasion force would be sent to Ireland."

Tyrconnell-born plague doctor Niall Ó Glacáin records enjoying O'Donnell's gracious hospitality at the Spanish court while also treating his exiled Prince for a bubonic plague sore.

During his time at court, O'Donnell also spent much of his time assisting the gathering of evidence for the court martial of Juan del Aguila. After two weeks, however, the King granted O'Donnell a generous pension and reassigned him to supervise naval preparations for another Spanish expeditionary force at Coruña.

The Spanish Council of State also reported to the King about O'Donnell, "His zeal and loyalty should be highly praised... He should be assured that His Majesty regards the Irish Catholics as his subjects."

Upon his own arrival on 21 March 1602, Juan del Aguila was met at the quay of Coruña by a livid Hugh Roe O'Donnell, whom del Águila told in a bouyant, positive tone, "Be of good comfort. We will have one more turn at Ireland." O'Donnell's reply is not recorded.

The Venetian Ambassador to Spain reported, "[The Spanish authorities] now insist that Águila made a mistake in coming to terms with the English and surrendering to them two places which he held. Some prophesy ill for him, declaring that he has escaped an honourable death in Ireland to meet with a shameful one in Spain."

The 31 July 1602 execution of the Duc de Biron, for allegedly plotting with Spanish backing to assassinate King Henri IV, brought France to the brink of entering the war as an ally of England and drastically increased the risk that further Spanish intervention in Ireland would result in French troops being dispatched there, as well.

Despite this fact, O'Donnell continued being told, according to Des Ekin, by the Spanish Council of State, "anything he wanted to hear." At the same time, according to intelligence reports received by Sir George Carew, O'Donnell's reputation remained, "great in Spain", while there was widespread, "dislike of Don Juan." Feelings regarding both men remained almost identical in Ireland.

Death and burial
In the Summer of 1602, Hugh Roe O'Donnell, suffering from, "anguish of heart and sickness of mind", finally left for Valladolid, "to go into the King's presence again to learn the cause of the delay." Instead, Hugh Roe O'Donnell unexpectedly fell ill at Simancas Castle.

Hugh Roe O'Donnell received the Last Rites and was attended by Archbishop of Tuam Fláithrí Ó Maol Chonaire and two refugee Franciscans from Donegal Abbey; Friars Muiris mac Donnchadh Ulltach and Muiris mac Seán Ulltach. After sixteen days of suffering, Hugh Roe O'Donnell died at Simancas Castle on 10 September 1602. He was 29 years of age.

O'Donnell's Last Will and Testament, written in his dying moments with his loyal retinue, is an extremely evocative and moving document. One original is preserved in Simancas and the other in the Chancellery archive in Valladolid.

Similarly to the explorer Christopher Columbus, Hugh Roe was buried in the Chapel of Wonders of the Franciscan monastery in Valladolid. Although both the monastery buildings and the land upon which they stood were confiscated, demolished, and sold by the anti-Catholic and Liberal Spanish Government of Queen Isabella II in 1837, the exact location of the tomb may have been discovered following a Spanish archaeological dig in May 2020. If Red Hugh O'Donnell's remains are successfully identified, they will be repatriated to Ireland for burial in County Donegal.

According to historian Jane Ohlmeyer, "If discovered intact, Red Hugh’s skeleton will reveal much about his stature and height, and possibly provide evidence if he suffered from childhood diseases, malnutrition, injuries (aside from the big toes he lost to frostbite after his 1591 mid-winter escape from Dublin Castle) or fractures, possibility associated with his martial lifestyle. Technology might allow researchers to recreate some of his facial features and to imagine what he looked like. Molecular analysis, especially of his teeth, might provide insights into what he ate and whether his diet changed over time. Remarkably, it will tell us how old he was when he was weaned as a baby and thereby provide a glimpse of Gaelic women, who are so absent from the historical record."

Thomas McGreevy's poem Aodh Ruadh Ó Domhnaill describes a search for his grave:


 * Juan de Juni, the priest said,
 * Each J becoming H,


 * Berruguete, he said,
 * and the G was aspirate,
 * Ximénez, he said then
 * And aspirated first and last.


 * But he never said
 * And -- it seemed odd -- he
 * Never had heard
 * The aspirated name
 * Of the centuries-dead
 * Bright-haired young man
 * Whose grave I sought.

McGreevy describes how, when


 * They brought
 * His blackening body
 * Here
 * To rest
 * Princes came
 * Walking
 * Behind it

And all Valladolid knew

And out to Simancas all knew

Where they buried Red Hugh.

The Anglo-Irish double-agent, James "Spanish" Blake, later claimed to have poisoned Red Hugh O'Donnell. The Calendar of the Carew Manuscripts, preserved in the Archepiscopal Library at Lambeth, 1601–1603, was copied and published in 1870 by Longmans, Green & Co. in London detailing the official preserved letters from Sir George Carew, Lord President of Munster during part of the Nine Years' War, to Charles Blount, Lord Mountjoy, who was nominated as Lord Lieutenant over Ireland by Queen Elizabeth I. Some of these letters were written in cipher, but the key to the cipher was to use a substitute letter six spaces earlier in the alphabet. In the letter from Carew to Mountjoy dated 28 May 1602, Carew reported to Mountjoy "One James Blake...took a solemn oath to do service...and is gone into Spain with a determination (bound with many oaths) to kill O'Donnell", and then another letter, written partially in cipher, was sent from Carew to Mountjoy dated 9 October 1602, "O'Donnell is dead... he is poisoned by James Blake, of whom your lordship hath been formerly acquainted...".

It is, however, unlikely that Red Hugh O'Donnell was poisoned. A more probable cause of death was the tapeworm that Simancas documents of the time stated to have been the cause of his demise. It should be said that spies and spymasters of the era often made improbable claims about their operations, and in this case as in many others like it, it is very likely that Carew exaggerated the success of his operative.

Even so, with O'Donnell's death, Spanish plans to send further assistance to the Irish clans were abandoned. According to Des Ekin, "The Duke of Lerma was in no hurry. He was still playing the long game. He aimed for peace with England, and Kinsale had achieved his aim of strengthening Spain's hand. True, Queen Elizabeth had inconsiderately refused to die while del Águila clung on his bridgehead: that was too bad. But still, for the price of a thousand Spanish deaths in Ireland, his Irish expedition had cost the Queen 6,000 to 10,000 of her best soldiers, diverted her from the Low Countries, and almost bankrupted her. It had worked out okay. Now it was time to move on. Soon, the Council of State would recommend a new policy towards the Irish: 'These people should be undeceived, so that they may be able to make the best terms [with the English] they can, bad as the consequences may be."

The Treaty of Mellifont that ended the war, was accordingly signed by Hugh O'Neill on 30 March 1603. For this reason, John McCavitt has recently stated about Hugh Roe O'Donnell, "Had he lived, this was a distinct possibility. It could have changed the course of Irish history forever."

Dynastic and local legacy
Aodh Ruadh was succeeded by the Tanist of Clan O'Donnell, his younger brother, Rory O'Donnell, as both Lord of Tír Chonaill and Chief of the Name of a still polarised Clan O'Donnell. After submitting in London to the newly crowned King James I, Rory, under the policy of surrender and regrant was required to renounce his traditional titles and was in return created hereditary Earl of Tyrconnell per letters patent of 4 September 1603, with the subsidiary title Baron of Donegal reserved for his heir apparent, but both titles were to be passed down by primogeniture rather than the Brehon law tradition of Tanistry. Rory was further granted the territorial Lordship of Tyrconnell per letters patent of 10 February 1604.

A 1614 Hiberno-Latin history of Donegal Abbey, however, harshly criticized the title of Earl as, "how inferior to that with which the Prince of Tyrconnell used to be acclaimed on the sacred rock of Kilmacrenan!"

Rory and his family ultimately joined the 1607 Flight of the Earls. In 1603, the last Chief of the Name and Lord of Tyrconnell to be acclaimed at the Rock of Doon was Red Hugh's treacherous cousin and brother in law Niall Garve O'Donnell; who now led the Clan with English backing.

For this reason, despite his praise for some elements of Niall Garbh O'Donnell's character, Philip O'Sullivan Beare also went on the record as a very harsh critic of him, Tiobóid na Long Búrca, Grace O'Malley, and other members of the Gaelic nobility of Ireland who similarly launched regime change wars within their clans with English backing. Having the benefit of hindsight regarding the long-term fallout from Niall Garbh's uprising against his Chief and many others like it nationwide, O'Sullivan Beare wrote, "The Catholics might have been able to find a remedy for all these evils, had it not been that they were destroyed from within by another and greater internal disease. For most of the families, clans, and towns of the Catholic chiefs, who took up arms in defense of the Catholic Faith, were divided into different factions, each having different leaders and following lords who were fighting for their estates and chieftaincies. The less powerful of them joined the English party in the hope of gaining the chieftainship of their clans, if the existing chieftains were removed from their position and property, and the English craftily held out that hope to them. Thus, short-sighted men, putting their private affairs before the public defence of their Holy Faith, turned their allies, followers, and towns from the Catholic chiefs and transferred to the English great resources, but in the end did not obtain what they wished for, but accomplished what they did not desire. For it was not they, but the English who got the properties of and rich patrimonies of the Catholic nobles and their kinsmen; and the Holy Faith of Christ Jesus, bereft of its defenders, lay open to the barbarous violence and lust of the heretics. There was one device by which the English were able to crush the forces of the Irish Chiefs, by promising their honours and revenues to such of their own kinsmen as would seduce their followers and allies from them, but when the war was over the English did not keep their promises."

Niall Garbh would prove no exception, as his alliance with Sir Henry Docwra collapsed due to a subsequent conflict over both money and power. Niall Garbh had been promised that he would rule Tyrconnell just as his ancestors had done, while Docwra had every intention of supplanting him and, along with other Royal officials, sought to frame him on charges of high treason, based on a nonexistent conspiracy with the Earl of Tyrone and the Spanish Crown. Iníon Dubh, who had outlived all her sons, belatedly took her revenge by informing Dublin Castle that Niall Garbh had encouraged Sir Cahir O'Doherty, whose lands in Inishowen Niall Garbh coveted, to launch O'Doherty's rebellion, and had then broken his word by refusing to raise his own clan and join the rising once it began. On 15 June 1608, Niall Garbh was arrested and imprisoned in October 1609 in the Tower of London. He remained there until his death in 1626.

As stated by Philip O'Sullivan Beare, the loss of their former protectors among the Gaelic nobility of Ireland drove the Catholic Church in Ireland deeper underground in the face of an escalating religious persecution that ended only with Catholic Emancipation in 1829. Historian and folklorist Tony Nugent accordingly lists twelve Mass rocks located throughout County Donegal that were used for illegal religious worship over the following centuries in defiance of the law, the Redcoats and the priest hunters. One is located beside the holy well near the Rock of Doon near both Termon and Kilmacrenan. The grave of Friar Rory O'Hegarty, who was captured and summarily executed by priest hunters while offering Mass near Buncrana in 1711 and buried where he fell, remains a local site of Christian pilgrimage.

Following the Irish War of Independence, the ascendant Fianna Fail political party began a policy of granted courtesy recognition as Chief of the Name to the senior male descendants of the Gaelic nobility of Ireland. With regard to the O'Donnell dynasty, the succession came down to a contest between the O'Donnell family of Newport House and the Duke of Tetuan of the Spanish nobility. The Irish State ultimately ruled in favor of Fr. Hugh O'Donnell, OFM, a Roman Catholic missionary in Zimbabwe who could document his descent from Manus O'Donnell, the second son of Niall Garbh and Nuala O'Donnell, who was killed in action while fighting for the Confederation of Kilkenny under the command of Eoghan Ruadh Ó Néill at the Battle of Benburb in 1646.

In September 2002, Eunan O'Donnell, BL, gave the Simancas Castle Address in honour of Red Hugh, during an O'Donnell Clan Gathering in Spain. In that same year, a monument upon the battlefield at Kinsale was unveiled by Nuala O'Donnell, the sister of Fr. Hugh O'Donnell, OFM. Following the death of Fr. Hugh O'Donnell, OFM on 11 July 2023, the White Wand of the Chiefdom and his seat in the Standing Council of Irish Chiefs and Chieftains were both inherited by his Tanist and distant relative, don Hugo O'Donnell, 7th Duke of Tetuan (d.1948).

During an interview with Peter Berresford Ellis, don Leopoldo O'Donnell y Lara, 6th Duke of Tetuán (1915-2002), don Hugo's father and the Irish State's then recognized Tanist of Tyrconnell, commented, "Being in my mid-eighties, perhaps I will not inherit the title of my forebears, nor even my son in his lifetimes. But one of my grandsons doubtless will. Our family, forced to flee from our native land to maintain our own existence, has never really abandoned Ireland, our patrimony nor our people of Tirconnell. We would sincerely wish to maintain their interest in the ancient Gaelic culture and civilization that once made Ireland the cradle of civilization during the grim, bleak days of the European Dark Ages."

Legacy
Red Hugh O'Donnell was highly praised in the Irish language chronicles of the era, the Renaissance Latin histories of Philip O'Sullivan Beare, and centuries of subsequent Irish bardic poetry for his personal commitment to the honour code of an Irish clan chief and, during the same era as the Irish Catholic Martyrs, his determined defense of the Catholic Church in Ireland against the religious persecution ordered by Queen Elizabeth I. Most notably, the Annals of the Four Masters, which was compiled between 1632 and 1636, either in a cottage beside the ruins of Donegal Abbey and just outside of Donegal Town or in a Franciscan house of refuge beside the River Drowes in County Leitrim and just outside Ballyshannon by Friars Mícheál Ó Cléirigh, Cú Choigcríche Ó Cléirigh, Fearfeasa Ó Maol Chonaire and Cú Choigríche Ó Duibhgeannáin, is a highly important source about his life from the perspective of Gaelic Ireland.

Also, the Classical Gaelic saga Beatha Aodh Ruadh Ó Domhnaill ("The Life of Red Hugh O'Donnell") by Lughaidh Ó Cléirigh, one of the five sons of Maccon Ó Cléirigh, the former official bard to the Chief of Clan O'Donnell, is another highly important source for Red Hugh's life and times. According to historian Hiram Morgan, "When Spanish interest in Ireland was renewed again in the Anglo-Spanish war of 1625–31, Lughaidh Ó Cléirigh wrote a biography of Red Hugh in the anachronistic style, placing him in a vaunted role in the Nine Years War in the hope of another O'Donnell leading the recovery of Ireland. In fashioning this bellicose Irish hero, Ó Cléirigh deliberately marginalised the role of O'Neill in the war."

This, according to James Henthorn Todd, would not at all have been unusual, however. In his introduction to the 1867 edition of Cogadh Gaedhel re Gallaibh, Todd explained, "It was unfortunately the custom of Irish scribes to take considerable liberties with the works they transcribed. They did not hesitate to insert poems or other additional matter, with a view to gratify their patrons or chieftains, and to flatter the vanity of their clan. It is to be feared, that for the same reason, they frequently omitted what might be disagreeable to their patrons, or scandalous to the Church; thus they were guilty of anachronisms and various mistakes, which have the effect of throwing discredit upon the works so transmitted to us, as disproving apparently their claim to antiquity."

At the same time, although Hugh Roe O'Donnell's posthumous reputation has been overshadowed in recent Irish nationalism by that of his father-in-law Hugh O'Neill, Red Hugh's leadership and tactical abilities were quite considerable, especially when considering that he was only 29 years old at the Battle of Kinsale in 1602. His personal charisma seems to have been particularly magnetic, and contemporary sources are united in their praise of his oratorical ability.

In 1977, the Aodh Ruadh Ó Domhnaill Guild was formed to seek his Cause for Canonization as a Saint of the Roman Catholic Church. His current title is Servant of God.

In 1991, a plaque was erected at Simancas Castle in commemoration of Red Hugh O'Donnell. A large cross in honour of Art MacShane O'Neill stands near the site of his death and secret burial in the Wicklow Mountains. Red Hugh and Art's 55 km. escape route from Dublin Castle to Glenmalure is also retraced by long-distance runners every January in "Art O'Neill's Challenge".

In popular culture

 * The Irish language and Sean-nós song Róisín Dubh, which remains one of the most popular Irish rebel songs ever written, is addressed in Red Hugh's voice to his wife, Róisín Ní Néill. The song is believed to have its origins in the rebel encampments during the Nine Years War, and has been attributed to a Tyrconnellian poet under the reign of Red Hugh. Conversely, music scholar Donal O'Sullivan claims there is no evidence it was composed that early.
 * In 1843, Michael Joseph MacCann wrote the song O'Donnell Abu in tribute, drawing on the tradition of romantic nationalism which was popular during the era.
 * In his 1861 poem Eirinn a' Gul ("Ireland Weeping"), Uilleam Mac Dhunlèibhe, an important figure in 19th century Scottish Gaelic literature, recalled the many stories about his fellow Gaels in Inis Fáil (Ireland) he had heard in the Ceilidh houses of Islay, before that island was emptied by the Highland Clearances. He then lamented the destruction wreaked upon the Irish people by both famine and similar mass evictions ordered by Anglo-Irish landlords. He particularly laments the loss of the chiefs of the Irish clans, who led their clansmen in war and provided "leadership of the old and true Gaelic kind". Mac Dhun Lèibhe comments sadly that the mid-19th century fighters for Irish republicanism had none of the heroic qualities shown by Red Hugh O'Donnell, Hugh O'Neill, and Hugh Maguire during the Nine Years War against Queen Elizabeth I. Sadly, but expressing hope for the future of the Irish people, Mac Dhun Lèibhe closes by asking where are the Irish clan warriors who charged out of the mist and slaughtered the armies of the Stranger at the Battle of the Yellow Ford and the Battle of Moyry Pass.
 * Aodh Ruadh CLG in Ballyshannon and Red Hughs Gaelic Athletic Association club at Crossroads, Killygordon, are named after Red Hugh O'Donnell.
 * He is the subject of James Clarence Mangan's poem Ceann Salla.
 * Hugh O'Donnell is the subject of the Irish ballad "If These Stones Could Speak", as featured on the Phil Coulter album Highland Cathedral.
 * Hugh O'Donnell serves as the main character in the 1966 Walt Disney feature film The Fighting Prince of Donegal in which he is portrayed by Peter McEnery.
 * O'Donnell is a major character in Brian Friel's 1989 play Making History. According to historian Jane Ohlmeyer, "Friel portrayed the youthful Red Hugh as fiery, headstrong, quick-witted, passionate, committed to Catholicism, and to the preservation of the values, language, and culture of the Gaelic world into which he had been born and reared... Though limited and often biased against Red Hugh, extant historical records largely validate Friel’s representation. They also recapture the complexities of Red Hugh’s highly militarised world, where local lords raided for cattle and reduced neighbouring lords to submission, and show Red Hugh to be a wily negotiator, an effective and pragmatic power broker, and a brave soldier."
 * In 1992, commemorating the 390th anniversary of the arrival of O'Donnell in Galicia, the Grammy Award-winning composer of Riverdance, Bill Whelan, brought together musicians from both Ireland and Galicia to perform his newest symphony From Kinsale to Corunna.