[1][2] Stephen's father was Gojslav II, the younger brother of Peter Krešimir IV of Croatia.
He was due to succeed Peter Krešimir IV but was sidelined by the people and clergy in 1075 who instead bestowed the title of king on Demetrius Zvonimir, previously a ban in Slavonia.
Here I was relieved of all my honours and had chosen the grabe, recommending the monastery's leader to mention me in his prayers.King Demetrius Zvonimir was a member of the junior Svetoslavić branch of the House of Trpimirović (descendants of Svetoslav Suronja).
Zvonimir's widow, Queen Jelena, reportedly plotted the inheritance of the Croatian Crown for her brother, King Ladislaus I of Hungary.
The war culminated in the Battle of Gvozd Mountain in 1097 leading to a personal union of Croatia and Hungary in 1102, ruled by Coloman.