If, as seems likely, the Dalriadic Scots towards the beginning of the 6th century established a footing in the islands, their success was short-lived, and the Picts regained power and kept it until dispossessed by the Norsemen in the 9th century.
While southern Scotland was thus English and Cymric, the north, from Cape Wrath to Lochaber, in the west, and to the Firth of Tay, on the east, was Pictland; and the vernacular spoken there was the Gaelic. The west, south of Lochaber to the Mull of Kintyre, with the isles of Bute, Islay, Arran and Jura, was the realm of the Dalriadic kings, Scots from Ireland (503): here, too, Gaelic was spoken, as among the " Southern Picts " of the kingdom of Galloway.
The Dalriadic settlers in Argyll and the Isles, the (Irish) Scots, were Christians in the Irish manner.
Thus the Dalriadic Scots had handed on the gift of Irish Christianity, with such literature as accompanied it in the shape of Latin, and reading and writing, to the northern English from Forth to Humber.
On the father's side he was descended from the Conall Gabhrain of the old Dalriadic Scottish kingdom, and the claims of father and son to the Pictish throne were probably through female descent.