After defeat of Arpa by Ali Padshah on 29 April 1336 and subsequent murder on 15 May 1336, Hasan Buzurg saw his chance and raised a child, Pir Husayn from Tabriz, a great-grandson of Möngke Temür, to claim the position in alliance with Hajji Taghay, the Sutaid claimant to Diyar Bakr in opposition to Ali Padshah. Pir Husayn was crowned in Anatolia on 20 July 1336 with the title "Muhammad Khan" and Hasan left for Iran, leaving his deputy Eretna behind to act as governor. Later on 24 July Hasan Buzurg and Muhammad met the forces of Musa Khan and 'Ali Padshah in the Ala-Tagh area; Musa was defeated and 'Ali Padshah killed. Hasan Buzurg pursued Musa on his way to Baghdad and created many losses for his enemy. He then proceeded to Tabriz where he put Muhammad on throne and married the granddaughter of Chupan and the wife of Abu Sa'id, Dilshad Khatun, who was pregnant with Abu Sa'id's daughter.