Tomislav was the first king of Croatia. He was probably the son of Dalmatian duke Muncimir. Tomislav himself became duke of Dalmatia around 910. He was crowned king at the fields of Duvno in 925 by order of Pope John X. During his life he united the Pannonian and Dalmatian duchys to form a united Croatian state.

He disappeared in 928, and it is still not known where or how he actually died. At the time of his death there was discord in the country over whether the liturgical language of the Roman Catholic Church in Croatia would be Latin or Croatian.

Tomislav is celebrated as the founder of the first united Croatian state. In the Croatian capital of Zagreb, there is a square dedicated to Tomislav. Near the place where he was crowned lies the town of Tomislavgrad (Tomislav's City).