Olsen

Danish and Norwegian: patronymic from the personal name Olaf, Olav (Old Norse Óláfr, Ólafr, variant Óleifr, earlier Anleifr, from proto-Scandinavian elements meaning ‘ancestor’ + ‘heir’, ‘descendant’). Olaf has always been one of the most common Scandinavian names; it continued to be popular in the Middle Ages, in part as a result of the fame of St. Olaf, King of Norway, who brought Christianity to his country c.1030. This surname, the second most common in Norway, is also established in England, notably in the Newcastle upon Tyne area.