This study brings within its scope all those areas of present-day Scotland (and the Isle of Man) influenced by Scandinavian peoples, whether Norwegian, Danish or Irish-Norse, from the beginning of the Viking raids to the death of the great earl of Orkney, Thorfinn 'the Mighty' (c. 1065). A maritime realm with no territorial unity, this area ranges from the Orkney and Shetland Islands across northern Scotland and down the Hebrides to the Irish Sea, and it came under lasting, and in some areas permanent, influence from Viking raids and Norse settlement.