In 1253 the Mongol Great Khan, Möngke, despatched his brother, Hülegü, at the head of a massive army, consisting of a fifth of all imperial forces. The objective of this expedition seems to have been the consolidation and expansion of the Mongol conquests in South-west Asia. Challenges to the Mongol ideology of world domination were targeted; after dealing with the Nizari Isma‘ilis of northern Persia, in 1257 Hülegü turned against the ‘Abbasid caliph himself. Baghdad was besieged and fell amid much destruction in February 1258. The caliph, al-Musta‘sim, was executed; estimates of the total killed vary widely, but Hülegü's own report provides a figure of 200,000. The Mongol army continued, northwards and westwards, around the Fertile Crescent, with the fragmented local states either accepting Mongol rule or being eliminated. The Mongol advance caused ripples of panic: the senior Ayyubid ruler in Damascus, al-Nasir Yusuf, sought, unsuccessfully, to placate Hülegü by sending his son with gifts; in Egypt the Mamluk Qutuz responded by deposing the nominal sultan, al-Mansur ‘Ali, taking the title for himself – this was no time for an infant to be ruler. In 1259 Mongol forces entered Syria, accompanied by forces provided by local rulers who had accepted Mongol suzerainty – including the Christian king Het‘um I of the Armenians and Prince Bohemond VI of Antioch. Aleppo was taken by storm in January 1260, and Damascus surrendered in March. Mongol forces campaigned south, as far as Gaza; apart from the Franks on the coast, all of Syria was effectively conquered, its former princes removed or accepting the new regime. Mongol rule in Syria was not to last, of course. The story of Hülegü's withdrawal and the defeat of his general, Kitbugha, by Sultan Qutuz at ‘Ayn Jalut in September, heralding the absorption of Syria into the Mamluk Empire, is well known. The year 1260, rather than marking a new chapter in Mongol expansion, instead marks its interruption: while Hülegü's successors, the Ilkhans, notably Ghazan (1295–1304), were to attempt the conquest of Syria, success was only ever as transient as it was then. The year 1260 marks, then, something of a high-water mark for Mongol expansion in South-west Asia.

A pictorial relict of this moment of Mongol triumph may exist, however, in a Syriac lectionary, originally produced for the Syrian Orthodox monastery of Mar Mattaï, near Mosul, and now in the Vatican.