Yongle Emperor's campaigns against the Mongols

The Yongle Emperor's campaigns against the Mongols happened from 1410 to 1424. It comprised five aggressive military expeditions by Ming China's armies against the Eastern Mongols, Oirat Mongols, and other Mongol tribes.

Background
During the reign of the Hongwu Emperor, the Mongol commander Naghachu surrendered to Ming China in 1387 and Tögüs Temür of the Northern Yuan was defeated by a Ming army led by General Lan Yu in 1388. Many Mongol tribes of Manchuria surrendered to Ming China and were subsequently incorporated into the Uriankhai Commanderies (known as the "Three Commanderies") to serve at the empire's northern frontier regions. However, the Oirat Mongols (the principal group of the Western Mongols) and Eastern Mongols remained hostile toward Ming China and each other.

The Ming court had dispatched the ambassador Guo Ji to the Eastern Mongols, demanding that they submit as a tributary to Ming China. However, in 1409, Bunyashiri of the Eastern Mongols executed the Ming ambassador. By contrast, Mahmud of the Oirat Mongols had sent a tributary mission to the imperial Ming court in 1408.

By establishing relations with the Oirats, Ming China effectively used them to offset the Eastern Mongols. There was growing enmity among the Ming court toward the Eastern Mongols for their refusal to accept tributary status and for the killing of a Ming emissary. Between 1410 and 1424, the Yongle Emperor led five military campaigns against the Mongols.

First campaign
In the winter of 1409, the Yongle Emperor made preparations for his military expedition. On 25 March 1410, he departed from Beijing on his military expedition against the Eastern Mongols. He brought with him an estimated 100,000 soldiers, even though the Mingshi gives an unlikely figure of 500,000 troops. They made use of 30,000 carts for transport. They traveled respectively to Xuanfu, Xinghe, and Kerulen.

The Ming army, advancing from Xinghe, stopped at Minluanshu, because the Yongle Emperor held a large military parade before the Oirat Mongol envoys. At the northern shores of Kerulen, he had carved into the rocks "Eighth year of the Yongle geng yin (year), fourth month ding you (month), sixteenth day ren zi [May 19, 1410], the Emperor of the Great Ming passed here with six armies during the punitive expedition against the barbarian robbers."

Bunyashiri wanted to flee from the advancing Ming army, but Arughtai disagreed with him. Therefore, the two Mongol leaders and their forces each separated to a different direction. The Ming army first gave chase to Bunyashiri. On 15 June 1410, they annihilated Bunyashiri's forces at the Onon River, but Bunyashiri managed to escape from the Ming army. Afterwards, the Ming army pursued Arughtai and his Mongol forces. They found and defeated his forces at Qingluzhen near Taor River, but he fled with his remaining men. The Yongle Emperor returned to Beijing on 15 September 1410.

Arughtai, after his defeat, attempted to establish a fragile relationship with the Ming China, because he feared their military power and desired Chinese goods through trade. Surrendering as a tributary to Ming China, an alliance was established between Arughtai and the Ming court. Late 1410, Arughtai sent tribute horses to the Ming imperial court and received trading privileges. In the spring of 1412, Mahmud's forces found and killed Bunyashiri during his flight from the Ming army.

Second campaign
The Ming court's attitude became more disdainful and negative toward the Oirat Mongols. The Yongle Emperor denied the Oirat chieftain Mahmud's request for the bestowal of rewards to his followers who had fought against Bunyashiri and Arughtai. Mahmud soon became angered by the Ming court's disregard toward him. He imprisoned Ming envoys, so the Yongle Emperor sent the eunuch envoy Hai T'ung in an unsuccessful attempt to secure their release.

In 1413, feeling threatened, Mahmud dispatched 30,000 Mongol troops to Kerulen River against Ming China. Late 1413, Arughtai informed the Ming court that Mahmud had crossed the Kerulen River, which would prove to trigger an imminent war with Ming China.

On 6 April 1414, the Yongle Emperor departed from Beijing to lead a military campaign against the Oirat Mongols. The Ming army advanced via Xinghe to Kerulen, to meet the Oirats in battle at the upper Tula River. The battle between the Ming army and Oirats ensued between the upper courses of the Tula and Kerulen rivers. The Oirats were overwhelmed by the heavy bombardment of the Ming cannons. They were greatly reduced and were forced to retreat. Mahmud and the puppet khan Delbek fled from the Ming army. The Yongle Emperor returned to Beijing in August 1414.

Arughtai excused himself from battle on the claim that he was allegedly unable to join due to illness. Even though Mahmud sought out reconciliation with Ming China, the Yongle Emperor looked to the thought with much suspicion. In any regard, before anything could happen, Arughtai had attacked and killed Mahmud and Delbek in 1416.

Third campaign


Arughtai hoped to gain rewards from the Ming court for his services against the Oirat Mongols. The Ming court bestowed only titles onto Arughtai and his mother, but did not give him the commercial privileges that he wanted. Arughtai became increasingly hostile and began attacking caravans at the northern trade routes to Ming China. By 1421, he had stopped sending tribute to Ming China. In 1422, he attacked and overran the frontier fortress Xinghe. This would prompt Ming China into launching a third military campaign.

Many senior officials opposed the expedition and urged the Yongle Emperor against launching it, because they found that it placed too great of an expense to the empire's treasury, but the emperor rejected his officials' words of advice. Eventually, resulting from their opposition, Minister of War Fang Bin committed suicide, while Minister of Revenue Xia Yuanji and Minister of Works Wu Zhong were imprisoned.

On 12 April 1422, the emperor and his army left Beijing toward Kulun. The Ming army supposedly comprised 235,000 soldiers according to Rossabi (1998). They had 235,146 men, 340,000 donkeys, 117,573 carts, and 370,000 shi of grain according to Perdue (2005). The Yongle Emperor led his army toward Dolon, where Arughtai was encamped. A force of 20,000 troops was detached to the Uriankhai Commanderies, which had fallen to Arughtai; they recaptured it in July.

The Ming army struck fear into Arughtai, who avoided engagement by fleeing far into the steppe. They responded with the destruction and plundering of Arughtai's encampments. The frustrating and unedifying situation caused the Yongle Emperor to shift his attention to mercilessly attacking and plundering three Uriankhai Mongol tribes who were not involved with Arughtai's hostilities. The plunders and attacks against any Mongols who found themselves in the path of Ming armies would be repeated in following campaigns. The Ming army returned to Beijing on 23 September.

Fourth campaign
In 1423, the Yongle Emperor launched a preemptive strike against Arughtai's forces. Leaving from Beijing in August, the Ming armies traveled through Xinghe and Wanquan. However, Arughtai withdrew and fled from the advancing Ming army once again. Esen Tügel, an Eastern Mongol commander, surrendered to Ming China. The Ming army returned to Beijing in December 1423.

Fifth campaign
Arughtai continued raiding the northern frontier at Kaiping and Datong. In 1424, the Yongle Emperor responded by launching his fifth campaign. He gathered his army at Beijing and Xuanfu. In early April, he departed from Beijing toward Arughtai's forces. They marched through Tumu and north to Kaiping. Once again, Arughtai avoided engagement by fleeing from the Ming army. Some of the Ming commanders wanted to pursue Arughtai's forces, but the Yongle Emperor felt that he had overextended himself and pulled back his army. On 12 August 1424, the emperor perished during the return to Ming China.