Around the year 500, the Irish kingdom of Dal Riata emigrated from Ulster to southwestern Scotland. Based on oral traditions, this invasion into Scottish territory was led by the three sons of Erc, the King of Dal Riata. It was during this “building stage” of the Scottish Kingdom of Dalriada that the Stone of Destiny and the Coronation Stone were brought by the Gaels into Argyll. The Coronation Stone was later brought to Scone, the capital of the Southern Picts. It was there that the Picts and Scots became unified in 844 under the guidance of Kenneth MacAlpine.
Anrothan O’Neill, an Irish prince from the O’Neill dynasty, took advantage of this new Scottish kingdom and gave up his rulership in Ireland to settle down in Argyll. From Anrothan’s line came a prominent lord named Aodha Alainn O’Neil, who had three sons: Gillachrist, Neill, and Dunslebhe. Gillachrist’s son, Lachlan, founded Clan MacLachlan, and Gillachrist’s brother, Neill, founded Clan MacNeil of Barra. Dunslebhe had two sons: Ewen and Fearchar. Ewen founded Clan Ewen of Otter, and Fearchar’s grandson founded Clan Lamont. Until the 13th century, Clan Lamont was known as MacKerracher in honour of Fearchar