Although initially he formed an alliance with the Seljuk Sultanate of Rûm against the Mongols, for reasons unknown he later changed his mind and began hostilities against the Seljuks. In 1230 he conquered Ahlat, (in what is now Bitlis Province, Turkey) an important cultural city of the era from the Ayyubids which led to an alliance between the Seljuks and Ayyubids. Jalal ad-Din on the other hand allied himself with Jahan Shah, the rebellious Seljuk governor of Erzurum.