Stjepan was a son of Croatian King

Kingdom of Croatia (medieval)

The Kingdom of Croatia , also known as the Kingdom of the Croats , was a medieval kingdom covering most of what is today Croatia and Bosnia and Herzegovina in the Balkans.Established in 925, it ruled as a sovereign state for almost two centuries...

 Svetoslav Suronja

Svetoslav Suronja

Svetoslav Suronja was King of Croatia from 997 to 1000. He was a member of House of Trpimirović. He reigned with the help of his Ban, Varda. His name was Svetoslav, but because of his physiology and, probably, his temper, he was nicknamed Suronja which could be translated as dark man or cold man....

, member of Trpimirović dynasty.

As his father was allied with Venetian Republic in Croatian civil wars and Croatian-Bulgarian wars

Croatian-Bulgarian wars

The Croatian-Bulgarian Wars were a series of conflicts that erupted three times during the 9th and 10th centuries between the medieval realms of Croatia and Bulgaria...

, as well as in campaign of Pietro Orseolo II against Croatia in 1000, it was decided to strengthen those bonds even more.

After the coup d'état

Coup d'état

A coup d'état state, literally: strike/blow of state)—also known as a coup, putsch, and overthrow—is the sudden, extrajudicial deposition of a government, usually by a small group of the existing state establishment—typically the military—to replace the deposed government with another body; either...

 in Venice

Republic of Venice

The Republic of Venice or Venetian Republic was a state originating from the city of Venice in Northeastern Italy. It existed for over a millennium, from the late 7th century until 1797. It was formally known as the Most Serene Republic of Venice and is often referred to as La Serenissima, in...

, Svetoslav Suronja and his family went to Hungary in exile and died.

Stjepan used the anarchy and made a conquest in Croatian Slavonia with Hungarians against the fratricide

Fratricide

Fratricide is the act of a person killing his or her brother....

 king. Stjepan later received the title Ban

Ban (title)

Ban was a title used in several states in central and south-eastern Europe between the 7th century and the 20th century.-Etymology:The word ban has entered the English language probably as a borrowing from South Slavic ban, meaning "lord, master; ruler". The Slavic word is probably borrowed from...

 of Slavonia.

His son, Dmitar Zvonimir, would later become the Croatian king in 1074.