Byzantine Attack

After a successful campaign against the Arabs on land and at sea, Byzantine forces turned towards Bulgaria and attacked it. Earlier that year, a devastating earthquake had struck the country, weakening the Bulgarians and bringing a year of famine. Also that year, Boris I concluded an alliance with Louis the German and had to send Bulgarian troops to reinforce his campaign against Great Moravia. The Bulgarian troops were poorly mobilised, and the Byzantine emperor took advantage of this.

When the Byzantines attacked, the troops had not been mobilised, and the attack ended in defeat for the Bulgarians.