Rashid-al-Din Hamadani
According to Rashid-al-Din Hamadani, Büri's mother was a wife of Chagatai Khan's slave. She was a beauty and Mutukan was attracted by her while she served in the Khan's ger. Mutukan made her pregnant and instead of marrying her, he took her baby, Büri. He was raised by Chagatai after Mutukan's death on siege of Bamiyan. He was characterized as a stubborn and brave person, especially when drunk.