Battle of Spercheios

As a response, a Byzantine army under Nikephorus Uranos was sent after the Bulgarians, who returned north to meet it. The two armies met near the flooded river of Spercheios. The Byzantines found a place to ford, and on the night of 19 July 996 they surprised the unprepared Bulgarian army and routed it in the battle of Spercheios. Samuel's arm was wounded and he barely escaped captivity; he and his son allegedly feigned death After nightfall they headed for Bulgaria and walked 400 kilometres (249 mi) home. 

The battle was a major defeat of the Bulgarian army. At first Samuil showed readiness for negotiations but upon the news of the death of Bulgaria's official ruler Roman in prison, he proclaimed himself the sole legitimate tsar and continued the war.