After the stunning victory in the battle of Adrianople (1205) the Bulgarians gained control of most of Thrace except several larger cities which Emperor Kaloyan wanted to capture.

In June 1205 he moved the theatre of the military actions to the south-west towards the domains of Boniface Montferrat, the King of Thessalonica and vassal of the Latin Empire.

The Crusaders tried to fight back in the vicinity of the town, but after the death of the commander Hugues de Coligny, were defeated and had to pull back to the town but during their retreat, the Bulgarian troops also entered Serres.

In the negotiations which followed Kaloyan agreed to give them safe conduct to the Bulgarian-Hungarian border.

In the following year the war against the Latin Empire and the local Byzantine nobility continued and the Crusader army was defeated once again in the battle of Rusion.