Complex sentence: Tryggve Olavsson (d.963) (Old Norse: "Tryggvi Ólafsson") was king of Viken (Vingulmark and Ranrike), son Olaf Haraldsson, king of Vestfold, and grandson of Harald Fairhair.
Split into simpler sentences: Tryggve Olavsson (d.963) (Old Norse: "Tryggvi Ólafsson") was king of Viken (Vingulmark and Ranrike). He was son Olaf Haraldsson, king of Vestfold, and grandson of Harald Fairhair.