After the success in the battle of the Rishki Pass (759) the Bulgarian Khan Vinekh showed surprising inaction and instead desired peace, which cost him the throne and his life. The new ruler, Telets, was a firm supporter for further military actions against the Byzantines. With his heavy cavalry he looted the border regions of the Byzantine Empire and on 16 June 763, Constantine V came out of Constantinople with a large army and a fleet of 800 ships, with 12 cavalrymen on each.

The energetic Bulgarian Khan barred the mountain passes and took advantageous positions on the heights near Anchialus, but his self-confidence and impatience incited him to go down to the lowlands and charge the enemy. The battle started at 10 in the morning and lasted until sunset. It was long and bloody, but in the end the Byzantines were victorious, although they lost many soldiers, nobles, and commanders. The Bulgarians also had heavy casualties and many were captured, while Telets managed to escape. Constantine V entered his capital in triumph and then killed the prisoners.