Olaf Gudrødsson (c. 810 – c. 860),[1] known after his death as Olaf Geirstad-Alf "Olaf, Elf of Geirstad" (Old Norse Ólafr Geirstaðaalfr), was a semi-legendary petty king in Norway. A member of the House of Yngling, he was the son of Gudrød the Hunter and according to the late Heimskringla, a half-brother of Halfdan the Black. Gudrød and Olaf ruled a large part of Raumarike. The Þáttr Ólafs Geirstaða Alfs in Flateyjarbók records a fantastical story of how he was worshipped after his death and on his own instructions, his body was then decapitated so that he could be reborn as Olaf II of Norway (St. Olaf).
Two not necessarily conflicting hypotheses identify Geirstad with Gjerstad, formerly Geirekstad in Agder, and with Gokstad (possibly also a contraction of Geirekstad) in Vestfold, the location of the mound Gokstadhaugen, where the Gokstad Ship was excavated. The theory that Olaf thus had a connection with the ship burial is unproven.[2]