 Chinese corps, expert in siege warfare, formed an integral part of the Mongol armies campaigning in the West.In 1259–1260 military alliance of the Franks knights of the ruler of Antioch, Bohemond VI and his father-in-law Hetoum I with the Mongols under Hulagu, in which they fought together for the conquests of Muslim Syria, taking together the city of Aleppo, and later Damascus.William of Rubruck, an ambassador to the Mongols in 1254–1255, a personal friend of Roger Bacon, is also often designated as a possible intermediary in the transmission of gunpowder know-how between the East and the West.