Answer
The Ottonian dynasty was a German dynasty that ruled the Holy Roman Empire from 919 to 1024. Stephen I of Hungary was a member of the Árpád dynasty, which ruled Hungary from 970 to 1301. Stephen I married Gisela of Bavaria, who was a member of the Ottonian dynasty. The marriage was arranged by Henry I of Germany, who was the brother of Gisela's father, Emperor Otto I.