 The fourth suggestion is the "Laithlind" or Lochlann hypothesis.This word appears in various forms in the early Irish literature and is usually assumed to refer to Norway itself, although some have preferred to locate it in the Norse-dominated parts of Scotland.Donnchadh Ó Corráin is a proponent of this view and claims that a substantial part of Scotland—the Northern and Western Isles and large areas of the coastal mainland—were conquered by the Vikings in the first quarter of the 9th century and that a Viking kingdom was set up there earlier than the middle of the century.