It was fought in the area of the highlands of Eastern Bosnia near the Drina River, the border area between the Kingdom of Croatia and the Bulgarian Empire. The Bulgarian ruler, Simeon, was a wise and able man with a restless and insatiable spirit. He spent his entire life fighting battles with neighboring countries. His basic aim was to defeat the Byzantine Empire and conquer Byzantium. To achieve his aim, Simeon overran the eastern and central Balkans several times, occupied Serbia and finally attacked Croatia.