Öljei Temür Khan (Mongolian:Өлзий Төмөр Хаанᠥᠯᠵᠡᠶᠢᠲᠡᠮᠦᠷ;Chinese:完者帖木兒汗), bornBunyashiri (Chinese:本雅失里,Sanskrit:प्रज्ञा श्री), (1379–1412) was a khagan of theNorthern Yuan dynasty, reigning from 1408 to 1412. He was a son ofElbeg Nigülesügchi Khan and successor ofGün Temür Khan. He was one of theBorjigin princes, such asTokhtamysh andTemür Qutlugh, backed byTimur to seize the throne.

Tsagaan Sechen tells that Bunyashiri (Buyanshir) was born in 1379.^[1] Twenty years after his birth, his father,Elbeg, was murdered by theOirats led by Bahamu and Ugetchi Khashikha. Later, Öljei Temür came to Central Asia after 1399. In 1402,Gün Temür Khan was killed byÖrüg Temür Khan or Guilichi in the struggle for the crown.

Due to internal struggles of the Mongols, the infant prince, Bunyashiri, fled toBeshbalik whereTimur's governor stationed. Timur ordered his governor to receive him kindly. Bunyashiri converted toIslam while he stayed at the court of Timur inSamarkand, thus making Öljei Temür Khan one of the very notable converts to Islam from the house ofKublai Khan.^[2][3]

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However, Örüg Temür Khan or Guilichi's victory was short-lived when he made several grave miscalculations. TheHistory of Ming says he replaced the Khagan title with a "Tatar Khan", alienating many other Mongol clans that were not "Tatar".Örüg Temür Khan also abolished the name "Great Yuan" (the official name of the formerYuan dynasty), because he needed to show friendly and subordinating gestures towards theMing dynasty so that he could consolidate his power and conquer other Mongol clans. This move was totally unacceptable to most if not all Mongols who wanted to recover their former glory and retakeChina proper by defeating the Ming Empire, which originally began asrebellions against the Yuan.

Taking the opportunity, Bunyashiri declared himself the new Khan with the title of Öljei Temür (Өлзий төмөр) at Beshbalik in 1403 and most Mongol clans soon rallied to his side.Arughtai of theAsud acknowledged hissuzerainty and was made chingsang (grandchancellor) to him. Oljei Temür Khan Bunyashiri's direct linkage ofGenghis Khan line only further strengthened his position: thoughÖrüg Temür Khan declared himself as Khan, his claim was not recognized by most Mongol clans. The Ming court stepped up itsdivide and rule tactics onNorthern Yuan Mongols by dispatching aeunuch, Wan An, to help Bunyashiri.^[4] Örüg Temür Khan Guilichi was soon defeated and although Guilichi's son continued to carry on the struggle for the position of the khan all the way till his death in 1425, they were never able to pose any serious threat to Bunyashiri's force, whose main enemy was the Ming Empire.

In 1409, the Ming court bestowed upon the Oirat leaders the title ofwang (王;vassal king or prince), exacerbating the Mongol–Oirat conflict. Öljei Temür Khan attacked theFour Oirats and failed to subjugate his stubborn subjects.

After hearing of a newBorjigin ruler consolidating his power over the Mongols, theYongle Emperor of theMing Empire demanded Öljei Temür Khan to submit. The Mongol court decided to decline it and detained the Ming envoy. Arughtai executed another Ming envoy in 1409.^[5] Apunitive expedition of the Ming Empire led byQiu Fu (丘福) wascrushed and the general and several other commanders lost their lives at the hand of Arughtai on 23 September 1409.^[6]

In response to the defeat of the Ming forces led by Qiu Fu, the enraged Yongle Emperor gathered a half-a-million-strong force to launch adecisive campaign against Öljei Temür Khan Bunyashiri. Before the battle, Öljei Temür Khan and Arughtai could not agree on a plan of action and simply moved in different directions.^[7] Arughtai decided to withdraw to the east of Mongolia while Öljei Temür Khan Bunyashiri headed west and set up hisordo (palace) on the banks of theOnon River. He was suddenly forced to accept a battle in which the Ming army won a resounding victory by nearly completely wiping out his entire army on 15 June 1410. Öljei Temür Khan Bunyashiri was barely able to escape with his life with only seven horsemen and his son while all the rest were lost. He was trying to reach theChagatai Khanate where he grew up. Capitalizing on the Khan's mistake, theOirat leader, Mahamud, killed him in 1412 and installed his own puppet khan,Delbeg (or Dalbag), on the throne in 1413.^[8] The death of Öljei Temür Khan Bunyashiri marked the temporary decline of theBorjigin line, and different Mongol clans fought each other for dominance.

• List of Northern Yuan khans

• 1412 deaths
• Northern Yuan khans
• 15th-century Mongol khans
• 15th-century Chinese monarchs
• 1379 births
• Converts to Islam
• Mongol Empire Muslims

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