The Ancestors of Malcolm II mac Kenneth, King of Scotland.
The Scots came from a kingdom in Ireland which was known as Dalriada. This kingdom corresponded roughly with the modern County Antrim in Northern Ireland. Very little is known about the kings of Dalriada, apart from their names. These are found in two mediæval sources, the Book of Ballymote and the Pedigree of the Scottish Kings. It should be noted that these sources were not written contemporaneously with the events which they describe. Often, they are copies of original material which is now lost to us, and they were written centuries after the fact. It is difficult to verify the information they give with supporting evidence, which makes the accuracy of that information doubtful. The list of the kings of Dalriada should therefore be regarded as legendary.
The Book of Ballymote gives 38 names in its genealogy, all presented as the direct line of kings. It begins with the name Angus Turbech of Tara. Tara, incidentally, is the ancient hall of the High Kings of Ireland. It is on a hill in County Meath, Éire, and its mention in a list of Kings of Dalriada implies that the Dalriada, or "race of Riada," are descended from the High Kings.
The genealogy ends with the name of Fergus, the son of Erc. With Erc we are on firmer ground: he was a king of Dalriada who died around 501 A.D.
The Dalriada crossed the North Channel from Ireland to Kintyre in Scotland, eventually establishing a kingdom around Argyll. The first record of this migration is in 258 A.D., when the Romans noted that Scots from the north attacked south as far as London. In time, the Dalriadan kingdom in Scotland overshadowed that in Ireland, and the kings made their home in Argyll, in its ancient capital of Dunadd.
The above mentioned Malcolm II mac Kenneth, King of Scotland, was a probable direct decendant of Fergus, the son of Erc, and, thus, by this account, the family of Bruce can again trace its ancestry to the ancient Kings of Ireland and Scotland.