The Battle of Drava River was fought between the army of Tomislav of Croatia and the forces of Hungarian tribes led by Grand Prince Zoltán, the youngest son of Árpád, founder of the Árpád dynasty. According to the Chronicle of the Priest of Dioclea from the late 12th century, Tomislav of Croatia defeated the Hungarians in battle. Others question the reliability of this account, because there is no proof for this interpretation in other records. The battle was followed by the unification of Duchy of Croatia and the territory of Lower Pannonia.