Haraldsson is a surname of Icelandic or Swedish origin, meaning son of Harald or son of Haraldur. Its Danish and Norwegian equivalent is Haraldsen. In Icelandic names, the name is not strictly a surname, but a patronymic. The name refers to: Godfrid Haraldsson (820–856), son of the Danish king Harald Klak. Guttorm Haraldsson (fl. 10th century), son of king Harald Fairhair of Norway. Sigvaldi Strut-Haraldsson (fl. 11th–12th century), chieftain of the Jomsvikings. Björn Ironside Haraldsson (fl. 12th century), Danish noble; father of Christina Bjornsdatter, a queen of Sweden.
https://en.wikipedia.org/wiki/Haraldsson