Battle of Mosynopolis

The Battle of Mosynopolis (Bulgarian: Битка при Месинопол) took place on 4 September 1207 at Mosynopolis, close to the modern town of Komotini, Greece, where Bulgarians defeated Latin Empire's forces.

In early 1207, the Bulgarian Tsar Kaloyan allied with Laskaris of Nicaea to attack the Latin Empire, forcing Emperor Henry to relinquish territory in Asia Minor. In response, Henry arranged a meeting with Boniface of Montferrat, who was King of Thessalonica, for a joint campaign against Kaloyan at Kypsella, Thrace, which Boniface agreed. On Boniface's return to Thessaloniki, he was ambushed near Mosynopolis by Bulgarian forces and was killed. Seizing the opportunity created by Boniface's death, Kaloyan besieged Thessalonica, but his sudden death abruptly ended the siege and created a power vacuum in Bulgaria that allowed Henry to consolidate the Latin Empire's territories.