Ibn Taymiyyah called on the Muslims to jihad once again and personally participated Battle of Marj al-Saffar against the Ilkhanid army. The battle began on 20 April of that year. On the same day, Ibn Taymiyyah declared a "fatwa" which exempted Mamluk soldiers from fasting during Ramadan so that they could preserve their strength. Within two days the Mongols were severely defeated and the battle was won.