Helen was born as a Hungarian princess and was the daughter of Árpád dynasty's king Bela I, sister to Ladislaus I of Hungary, granddaughter of Polish king Mieszko II Lambert.

Helen became queen of Croatia during her marriage with Croatian king Demetrius Zvonimir, a distant relative whom she married in 1063.

Helen had excellent family connections, being an aunt to Irene, the mother of the Byzantine Emperor Manuel I Komnenos.

Upon the death of Zvonimir, Helen was said to have been quietly plotting the inheritance of the Croatian Crown for her brother, the King of Hungary.

This situation caused a decade of war and instability in the kingdom, resulting in the personal union of Croatia and Hungary that lasted until 1918.