Kingdom of Strathclyde
By 6th century, four major circles of influence had emerged in northern Britain. In the east were the Picts, whose federation of kingdoms stretched from the river Forth to Shetland. In the west were the Irish-Gaelic speaking Dál Riata with their royal fortress at Dunadd in Argyll. In the south was the Brythonic Kingdom of Strathclyde, descendants of the Roman-influenced tribes. Finally, in the south east, the “Angles”, Germanic invaders who held the Kingdom of Bernicia (later the northern part of Northumbria).
Strathclyde, or Alt Clut (named after the Brythonic name for Dumbarton Rock, the Medieval capital of the Strathclyde) emerged sometime in the 5th century. In 642, led by Eugein son of Beli, they defeated the men of Dál Riata at the Battle of Strathcarron. The kingdom suffered a number of attacks from the Picts of Fortriu and later the Northumbrians in the 2ed half of the 8th century. They lost the region of Kyle in the south-west of modern Scotland to Northumbria, and the last attack may have forced the king Dumnagual III to submit and become a vassal. After this, little is heard of Strathclyde until Alt Clut was burnt and probably destroyed in 780 by the Vikings Amlaib and Ivar, and the capital was moved to Gorvan. In the next decades many Vikings settled the country.
During the second half of the 10th century and onwards the kingdom changed hands between the English and the Scots who placed puppet kings to rule it or in other occasions annexed parts of it. In 1107 what was left of the kingdom was annexed by Alexander I of Scotland and became the appanage (seat of the crown prince) for his kingdom.