Tomislav of Croatia

Tomislav (pronounced [tǒmislaʋ], Latin: Tamisclaus) was a ruler of Croatia in the Middle Ages. He reigned from around 910 until 928, first as a duke (Latin: dux Croatorum) of the Duchy of Croatia, and then became the first king (rex Croatorum) of the Croatian Kingdom by the year 925. At the time of his rule Croatia forged an alliance with the Byzantines during their struggle with the Bulgarian Empire, with whom Croatia eventually went to war that culminated in the decisive Battle of the Bosnian Highlands in 926. To the north there were often conflicts with the Principality of Hungary, Croatia managed to keep its borders and to some extent expand on the disintegrated Duchy of Pannonia.

Tomislav attended the Church Council of Split in 925, convened by Pope John X to discuss the use of Slavic language in liturgy and the ecclesiastical jurisdiction over Croatia and the Byzantine Theme of Dalmatia. Although the Pope sought to prohibit Slavic liturgy, the Council did not share his view, while jurisdiction was given to the Archbishop of Split instead of the Croatian Bishop Gregory of Nin. Since the historical sources about Tomislav are scarce, the exact year of his accession and his death are not known. The rule of his successors was marked by a series of civil wars in Croatia and gradual weakening of the country.