Austro-Turkish War (1716–1718)

The Austro-Turkish War (1716–1718) was fought between Habsburg monarchy and the Ottoman Empire. The 1699 Treaty of Karlowitz was not an acceptable permanent agreement for the Ottoman Empire. Twelve years after Karlowitz, it began the long-term prospect of taking revenge for its defeat at the Battle of Vienna in 1683. First, the army of Turkish Grand Vizier Baltacı Mehmet defeated Peter the Great's Russian Army in the Russo-Turkish War (1710–1711). Then, during the Ottoman–Venetian War (1714–1718), Ottoman Grand Vizier Damat Ali reconquered the Morea from the Venetians. As the guarantor of the Treaty of Karlowitz, the Austrians threatened the Ottoman Empire, which caused it to declare war in April 1716.

In 1716, Prince Eugene of Savoy defeated the Turks at the Battle of Petrovaradin. The Banat and its capital, Temesvár, were conquered by Prince Eugene in October 1716. The following year, after the Austrians captured Belgrade, the Turks sought peace, and the Treaty of Passarowitz was signed on 21 July 1718.

The Habsburgs gained control of Belgrade, Temesvár (the last Ottoman fortress in Hungary), the Banat region, and portions of northern Serbia. Wallachia (an autonomous Ottoman vassal) ceded Oltenia (Lesser Wallachia) to the Habsburg monarchy, which established the Banat of Craiova. The Turks retained control only of the territory south of the Danube river. The pact stipulated for Venice to surrender the Morea to the Ottomans, but it retained the Ionian Islands and made gains in Venetian Dalmatia.

Siege of Belgrade
On the advice of one of his generals, Eugene chose to cross the Danube, approaching Belgrade from the east and rear, surprising the Ottomans who did not expect the enemy to cross the river at that point. He established the first camp at Višnjica the highest point, some 5 km away from Belgrade. On 18 June the city was surrounded. Eugene deployed his artillery while the Imperial troops began digging trenches, in a semicircle from the Danube to the Sava, both in front of the fortress and at the rear to cover the imperials in the event of the arrival of a Turkish relief army. The fortification lines, 16 km long, were completed on 9 July, providing a connection between Danube and Sava rivers. The right side of the camp was protected by the Habsburg Danube flotilla. Count von Hauben was sent to establish a bridgehead west of the Sava for a supply and communication route to Petrovaradin and a liaison to the troops in Zemun.

The Ottoman defenders in Belgrade numbered 30,000 men, under the command of Serasker Mustafa Pasha, who had been commander of the Temeşvar Fortress. He was one of the best Ottoman commanders. Mustafa was ready to fight until reinforcements arrived, bombarding the imperial soldiers from above. Prince Eugene was informed that the huge Ottoman army of about 140,000 men sent to relieve Belgrade was approaching under the command of Grand Vizier (Hacı) Halil Pasha. This army arrived on 28 July. However, instead of taking action against the besiegers, they began to dig trenches. Prince Eugene's troops were caught between the fortress and the relief army in a dangerous crossfire. Because of losses to cannon fire as well as malaria, the strength of the Austrian army slowly diminished. The Ottomans wanted to let the enemy wear themselves down in a long siege. While the situation was rather worrying for the imperial troops, the Grand Vizier chose to wait. Even when 40,000 Crimean Tatars arrived on 12 August, Halil Pasha, still reluctant to fight Eugene's army, chose to gather another war council instead of attacking.

On 14 August, Belgrade was suddenly shaken by a powerful explosion: a mortar shell launched from Zemun struck the ammunition store inside the fortress killing 3,000 defenders in the explosion. Prince Eugene immediately chose to confront the massive Ottoman relief army. Summoning his commanders for a council of war, he ordered a surprise attack, planned in the smallest details, for the night between 15 and 16 August. "Either I will take Belgrade or the Turks will take me"

- Prince Eugene to his generals, 15 August 1717

According to the war order, the infantry under Field Marshal Charles Alexander, Duke of Württemberg would hold the center, while the imperial cavalry commanded by Hungarian Field Marshal Count János Pálffy would form at the left and right wings of the entrenchment. Apart from eight battalions, about 10,000 men, left under Field Marshal Count George de Brown to hold the trenches facing the fortress, and four infantry battalions under Count Peter Josef de Viard protecting the camp and the bridgeheads, the entire army was involved in the attack. In total this included 52 infantry battalions, 53 grenadier companies, and 180 cavalry squadrons, supported by 60 cannons, a force of about 60,000 soldiers.

On the Ottoman right side were 10,000 county soldiers under Rumeli Beylerbeyi as well as 20,000 sipahis and armored silahdar. On the left were 10,000 province soldiers and the 40,000 Crimean cavalry under Beylerbeyi Maktulzade Ali Pasha. In the center were 80,000 janissaries, a total of 160,000 soldiers.

The attack started as scheduled before midnight of 15 August, a heavy fog arose covered the battlefield, according to Lieutenant General of Infantry Maffei the fog was so thick it quickly became impossible to distinguish between friend and enemy. Württemberg advanced the Imperial center with Count Pálffy's cavalry on left and right. The night attack surprised the Ottomans and they woke in panic and confusion. However several Ottoman infantry battalions managed to corner the right side of Pálffy's cavalry after it lost its way in the fog this already disrupting the order of war. The Ottoman infantry opened fire with support from their left Sipahi cavalry. General Count Claude Florimond de Mercy with the second cavalry line attacked immediately in support of Pálffy, followed by the infantry of Maximilian Adam Graf Starhemberg. The thrust succeeded in pushing the Ottomans back all the way to their trenches. Because of the simultaneous Habsburg cavalry and infantry attack, the Ottomans retreated leaving their batteries.

After the first hours of fighting, while the sun rose but the intense fog still covered the battlefield, the Ottomans perceived an opening in the center of the Austrian array and attacked in force. The Ottomans found themselves in between the two wings with a clear advantage but seemed to be unaware of it. Prince Eugene understood that he could turn the situation to his advantage since he could anticipate now the Ottoman battle plan. Hhe ordered von Braunschweig-Bevern's second infantry line to counterattack, placing the Bavarian troops in the front. Then Eugene personally led the attack at the head of the Austrian cavalry reserves. Although Eugene was wounded, his cuirassiers and hussars struckd the flanks of the Ottoman janissaries in a tremendous onslaught. The left and right Habsburg wings managed to finally restore contact with the help of the central infantry. Eugene's attack completely changed the situation. It not only pushed the enemy back but also took the trenches, throwing the Ottoman camp into turmoil and causing many soldiers to flee. The Ottoman 18-gun battery on the Badjina Heights was captured and the remaining troops withdrrw to the camp where the Grand Vizier ordered a full retreat.

After 10 hours of fighting, the battle was over. Ottoman losses numbered between 15,000 and 20,000 men, including Erzurum governor Mehmet Pasha, Chief Admiral Ibrahim Pasha and Rumeli governor Vezir şatr Ali Pasha, 5,000 wounded soldiers and all of their 166 artillery pieces. The Austrians suffered fewer than 6,000 losses, Pálffy, Württemberg, and the young Maurice de Saxe were wounded, and Prince Eugene was wounded for the 13th time. Killed included Field Marshal Count Hauben, 87 officers and 1767 soldiers; wounded 223 officers and 3179 soldiers.

The Grand Vizier and the remains of his army escaped first to Smederevo then Niš. They were harassed by Serbian infantry, Serbian militias, Hajduks, and the Habsburg light cavalry made up of Hungarian hussars.

The trophies of war included nearly two hundred cannons, one hundred and fifty flags, nine horsetails, and the captured war chest. James Oglethorpe, an aide de camp of the prince, reported that Eugene had a Te Deum performed in the tent of the Grand Vizier on 19 August after taking possession of it.

The garrison, deprived of relief and with soldiers about to revolt, surrendered five days later to the Austrians, on 21 August, in exchange for safe passage from the city, which Eugene granted; 25,000 residents were given the right to freely leave the city honorably. The entire Muslim population together with the remaining Ottoman garrison troops left unhurt taking their basic possessions with them.

Aftermath
Belgrade was transferred into Habsburg Austrian hands after 196 years of Ottoman rule. Prince Eugene crowned his career with a great victory and the Ottoman dominance in the Balkans suffered a severe blow. A year later, the Treaty of Passarowitz was signed, completing the Treaty of Karlowitz of 1699. Austria obtained at the expense of the Ottoman Empire the Banat of Temesvár which returned to the kingdom of Hungary, Belgrade, northern Serbia, Lesser Wallachia (Oltenia), and other neighboring areas. Austria reached its maximum expansion in the Balkans. Prince Eugene of Savoy crowned his career as the most successful military leader of his time, and retired from active military service. After this defeat, the Ottoman Empire would no longer hope to expand in Europe but merely sought to retain conquered territory. Belgrade would remain a territory under the domination of Austria for over twenty years until new Ottoman–Habsburg rivalries resulted in the city being reconquered by the Ottomans.