Having dealt with the pressure from the Magyars and the Byzantines, Simeon was free to plan a campaign against the Magyars looking for retribution. He negotiated a joint force with the Magyars' eastern neighbours, the Pechenegs.

Using a Magyar invasion in the lands of the neighbouring Slavs in 896 as a casus belli, Simeon headed against the Magyars together with his Pecheneg allies, defeating them completely in the Battle of Southern Buh and making them leave Etelköz forever and settle in Pannonia. Following the defeat of the Magyars, Simeon finally released the Byzantine prisoners in exchange for Bulgarians captured in 895.