A Romano-British kingdom of north-west England and south-west Scotland: formed in the 2nd century ad, it survived until the 11th century, the last kingdom of the Britons to disappear. It survived invasions by Eadbert of Northumbria (750 and 756), plundering by the Danes (870), and the temporary loss of its independence (920) to Edward the Elder of England. Duncan I acquired Strathclyde in 1018 and united it with three other regions to found the kingdom of Scotland (1034).