Originally, tradition held that the Dal Riada Scots arrived around 500 AD, from northern Ireland and headed by Fergus Mor mac Erc. However, more recent information implies that the Scots arrived earlier than that, in smaller less populous waves starting perhaps 200 years before. There is evidence that Scots and Picts fought together against Romans in the fourth century. They first settled in the Argyll region of western Scotland. By the 7th century, the Dal Riada Scots were a marked presence on the western islands and along the mainland sea lochs.

Early Scotti settlements included:

Dunadd/Dun Att (on the river Add, south of Kilmartin,
Dun Ollaigh/Dunollie (Oban),
Tairpert/Tairpert Boittir/Tarbert (south side of Kintyre),
Dun Aberte/Dunaverty (south side of Kintyre).