In the 17th century, George Mackenzie, 1st Earl of Cromartie wrote a history of the Mackenzies, which included a genealogy of the MacLeods of Lewis (from whom he was also descended). Cromartie's genealogy listed Leod as a son of Harald, son of Godred Donn. Later genealogies, however, made Leod a son of Olaf the Black—genealogies found in Sir Robert Douglas of Glenbervie's "Baronage of Scotland", of 1798; and the "Bannatyne manuscript", which dates to about 1830. In the "Baronage of Scotland", Glenbervie stated that he had obtained information from the MacLeods of Dunvegan which was allegedly based upon information found within the mediaeval "Chronicles of Mann" and William Camden's 17th century "Britannia"—however, neither of these two works make any mention of Leod at all. In 1977, historian William Matheson rejected the traditional descent from Olaf the Black on the basis that it is unsupported by any facts whatsoever, and that it is also contradicted by earlier Gaelic-language genealogies which may be more authentic.