The conflict started when the Mamluk Sultan Baibars, seeking to take advantage of the weakened Mongol domination, sent a 30,000 strong army to Cilicia and demanded that Hethum I of Armenia abandon his allegiance to the Mongols, accept himself as a suzerain, and give to the Mamluks the territories and fortresses Hetoum has acquired through his alliance with the Mongols.

The confrontation took place at Mari, near Darbsakon on 24 August 1266, where the heavily outnumbered Armenians were unable to resist the much larger Mamluk forces.

Following their victory, the Mamluks invaded Cilicia, ravaging the three great cities of the Cilician plain: Mamistra, Adana and Tarsus, as well as the harbour of Ayas. Another group of Mamluks under Mansur took the capital of Sis. The pillage lasted 20 days, during which thousands of Armenians were massacred and 40,000 were taken captive.