The Bishop of Reykjavík is the head of the Roman Catholic Diocese of Reykjavík, part of the Catholic church in Iceland. The Norsemen who settled in Iceland from the end of the ninth century worshipped the Æsir (the Norse gods). The country converted about 999. Upon the death of Haakon VI of Norway in 1380, his son Olaf, who since 1376 had ruled Denmark, ascended the Norwegian throne and thus effected a centuries-long union of Denmark and Iceland, which later facilitated the spread of Lutheranism during the Reformation. The Althing (Icelandic parliament) was not suppressed until 1800.