The tribal leader named by the Seanchaí is Gilli Chattan Noir, chief of the Catti, during the reign of King Alpine (A.D. 831-834), from whom descend the general name of Chattan Clan. The ancient title (Celtic) of the Earls of Sutherland is “Morfhear chat,” Lord Cat; literally Greatman Cat. The Seanchaí were traditional Gaelic storytellers - servants to the chiefs of the tribe and custodians of important information for their clan.
In 1010, Robert the chief of the Clan Cattan, fought against the Norsemen. He slew Comus, the Viking leader of the invaders, and gained a complete victory, for which Malcolm II gave him the lands of Keith in East-Lothian, the lands of Glenloy and Loch Arkaig. It was here that Tor Castle became the clan chief's seat.
According to the manuscript genealogies of Highland clans, believed to be written by MacLauchlan, bearing the date of 1467, contains the origin of the Davidsons attributed to a certain Gilliecattan Mhor, 1st chief of Clan Chattan in the time of 1085 –1153. The name of Gillechattan Mor, meant the great servant of St Catan, whose Abbey was at Kilchattan on the isle of Bute in the Firth of Clyde.
One of Gilliecattan Mhor’s great grandsons was named Muriach (or Murdoch) MacPherson who was parson of Kingussie in Badenoch. He became 4th Chief of Clan Chatten upon his brother's death. The name MacPherson, according to different spellings comes from the Gaelic Mac a’ Phearsain and means ‘Son of the Parson’. A Parson before the Reformation in Scotland, was not a priest, but the parson was the steward of church property, responsible for the collection of tithes. Muriach’s great granddaughter married Angus MacKintosh in 1291, the 6th Chief of Clan MacKintosh and he would also become 7th Chief of Clan Chattan.
Angus’ daughter Slane MacKintosh, married Donald Cromyn , the third son of Robert Comyn who in turn was a grandson of John III Red Comyn, Lord of Badenoch, chief of the Clan Comyn. Their son was David Dubh, also known as Black David, in Gaelic Daibhidh Dhu, pronounced Davie Doo. David and his followers became known as the Clan Dhai because the Comyn name had already been prescribed in 1320. Unlike many Highland clan names which begin with the Gaelic 'mac' meaning 'son of', the son of David took the non-Gaelic form and became David-son. David Dubh of Invernahaven, Chief of Davidsons, having married the daughter of Angus, 6th of MacKintosh, sought the protection of his brother–in-law, William MacKintosh, 7th Chief of MacKintosh and 9th Chief of Clan Chattan, shortly before 1350, and thus Clan Davidson became part of the Chattan Confederation.
This was critcal for their Clan’s survival because their ancestory was related to King John Balloil of Badenoch and they were part of a branch of the Comyns that was on the wrong side of history – enemies of Robert de Brus, 5th Lord of Annandale, grandfather of Robert the Bruce. Safely under the protection of Clan Chattan, the Davidsons would grow into one of the most important of the families within the Chattan federation. Their land was located at Invernahavon, just north of the junction of the rivers Spey and Truim alongside the MacPhersons.