Fergus I of Dalriada, also known as Fergus Mor Mac Earca was king of Dalriada. He reigned from about 500-501. He is sometimes considered the father of Scotland.

"In AD 498, Fergus Mor Mac Earca, in the twentieth year of the reign of his father, Muredach, son of (Eugenius, or) Owen, son Niall of the Nine Hostages, with five more of his brothers, viz., another Fergus, two more named Loarn, and two named Aeneas, with a complete army, went into Scotland to assist his grandfather Loarn, who was a King of Dalriada, and who was much oppressed by his enemies the Picts, who were in several battles and engagements vanquished and overcome by Fergus and his party. Whereupon, on the king's death, which happened about the same time, the said Fergus was unanimously elected and chosen king, as being the Blood Royal, by his mother; and the said Fergus was the first absolute king of Scotland, of the Milesian Race: so the succession continued in his blood and lineage ever since to this day."

Annals of the Four Masters.

He is an ancestor to Matilda of Scotland, grandmother of Henry II of England, and, subsequently is an ancestor to the present-day British royal family, including Elizabeth II, Queen of Great Britain and Northern Ireland.