The Laigin, or Dumnonii, were the third
ethno-tribal group to come to Ireland, coming from Gaul shortly before the Gaels
themselves, sometime during the first century B.C. Branches of the Dumnonii settled first
in the Devon-Cornwall area before others moved on to Ireland (Chapter III).
In southern Britain their kingdom gave its name to Devon (Dumnonia). In
the time of King Arthur (ca. A.D. 500), as the tribe most closely associated with that
great Pendragon, these Devon Domnonii established a dual kingdom which included the north
coast of Brittany (Domnonie), from whose royal house eventually sprang the House of
Stewart (which house inherited the crown of the Scots in 1371 and that of England in
1603). The Stewarts are covered under the chapter on the Normans, having come to Scotland
in the wake of Norman conquest of England, in which they served as allies of the dukes of
Normandy.
In Ireland the Dumnonii were generally known as the Laigin, and
originally became overlords in the southeastern and central regions, and in Connacht. From
there they later spread to other parts of Gaeldom, as we shall see.