Krum's campaigns Simeon I's campaigns Sviatoslav's invasion of Bulgaria Byzantine conquest of Bulgaria Uprising of Peter Delyan Second Bulgarian Empire The Battle of Ostrovo occurred in 1041 near Ostrovo, an area close to the lake of the same name in modern Northern Greece.

In 1040 Peter Delyan, an illegitimate relative of Samuel, the Bulgarian Tsar,[1] led an uprising against the Byzantines and was proclaimed Emperor of Bulgaria.

He quickly occupied the western Balkan lands from Belgrade to Larissa but in the next year he was betrayed by his cousin Alusian, who blinded him with a knife after he got drunk during a feast.

[2] Alusian, who initially sought to lead the army against the Byzantines, secretly negotiated a deal with Emperor Michael IV at Mosynopolis and was rewarded with a title of magistros.

[1] As a result, the uprising was repulsed and the emperor entered Bulgaria, which remained a Byzantine province until 1185.