In 1260, Hulagu Khan had invaded the Middle East all the way to Palestine. Before he could follow up with an invasion of Egypt, he was called back to Mongolia. He left two tumens (20,000 men) under general Kitbuqa. This army was defeated at the Battle of Ain Jalut and the Mongols were expelled from Palestine and Syria. Hulagu returned with another force, but his invasion was permanently delayed after his cousin Berke of the Golden Horde (who had converted to Islam) secretly allied with the Mamluks and instigated a civil war in the Caucasus.