Kaloyan gave shelter to Byzantine refugees and persuaded them to stir up riots in Thrace and Macedonia against the Latins. The refugees, according to Robert of Clari's account, also pledged they would elect him emperor if he invaded the Latin Empire. The Greek burghers of Adrianople (now Edirne in Turkey) and nearby towns rose up against the Latins in early 1205. Kaloyan promised that he would send them reinforcements before Easter. Considering Kaloyan's cooperation with the rebels a dangerous alliance, Emperor Baldwin decided to launch a counter-attack and ordered the withdrawal of his troops from Asia Minor. He laid siege to Adrianople before he could muster all his troops. Kaloyan hurried to the town at the head of an army of more than 14,000 Bulgarian, Vlach and Cuman warriors. A feigned retreat by the Cumans drew the heavy cavalry of the crusaders into an ambush in the marshes north of Adrianople, enabling Kaloyan to inflict a crushing defeat on them on 14April 1205.