Olvir Rosta, also known as Aulver Rosta, is a character within the mediaeval Orkneyinga saga, who is purported to have lived during the early 12th century. His Old Norse byname, rósta, means "brawl", "riot". His name, and byname, appear variously in English secondary sources.

Leod was the eponymous ancestor and founder of Clan MacLeod and Clan MacLeod of Lewis. Almost nothing is known about him and he does not appear in any contemporary records. Tradition dating to the late 18th century made him a son of Olaf the Black who was King of Man. Heraldic evidence, dating to the late 17th century, is considered to be the earliest evidence of descent from Olaf the Black. However, in recent years, this traditional lineage has been challenged and is no longer considered fact by one historian.