Boris of Bulgaria invades Thrace
Plovdiv, BulgariaBoril of Bulgaria invades Thrace. Henry makes an alliance with Boril's rebellious cousin, Alexius Slav. The Latins inflict a crushing defeat on the Bulgarians at Philippopolis and capture the town. Alexius Slav swears fealty to Henry through the traditional Byzantine ceremony of proskynesis (involving a kiss on Henry's feet and hand).