He was the oldest son of Krešimir I and succeeded him as king in 945. During his reign, Croatia suffered a civil war started by the followers of his brother, Michael Krešimir II. Because of this, Miroslav lost most of his lands in Bosnia, and the Byzantines wanted to take back his holdings in Dalmatia.
In his time, it is known that the Croatian navy was reduced to only 30 ships, while the infantry and cavalry had even more devastating losses in the civil war until Miroslav was finally killed by Pribina, Ban of Croatia in 949, and his younger brother, Michael Krešimir II, succeeded him as king.
Horvat, Rudolf (1924). "24. Nasljednici kralja Tomislava". Povijest Hrvatske I. (od najstarijeg doba do g. 1657.) (in Croatian).
Jadrijević, Ante (1967). "Smrt hrvatskih kraljeva Miroslava i Zvonimira"(PDF). Church in the World (in Croatian). 2 (1). Catholic Faculty of Theology, University of Split: 45–59. Retrieved 31 December 2014.
