Tomislav of Croatia

Tomislav was the first king of Croatia. He became Duke of Croatia c. 910 and was crowned king by 925, reigning until c. 928. During Tomislav's rule, Croatia forged an alliance with the Byzantine Empire against Bulgaria. Croatia's struggles with the First Bulgarian Empire eventually led to war, which culminated in the decisive Battle of the Bosnian Highlands in 926. In the north, Croatia often clashed with the Principality of Hungary; the state retained its borders and, to some extent, expanded with the disintegrated Lower Pannonia.