Ata-Malik Juvayni
In preparation for his invasion, Hulagu raised a large expeditionary force, conscripting one out of every ten military-age males in the entirety of the Mongol Empire, assembling what may have been the most numerous Mongol army to have existed and, by one estimate, 150,000 strong. Generals of the army included the Oirat administrator Arghun Agha, Baiju, Buqa Temür, Guo Kan, and Kitbuqa, as well as Hulagu's brother Sunitai and various other warlords. The force was also supplemented by Christian forces, including the King of Armenia and his army, a Frankish contingent from the Principality of Antioch, and a Georgian force, seeking revenge on the Muslim Abbasids for the sacking of their capital, Tiflis, decades earlier by the Khwarazm-Shahs. About 1,000 Chinese artillery experts accompanied the army, as did Persian and Turkic auxiliaries, according to Ata-Malik Juvayni, a contemporary Persian observer.