O'Rahilly's historical model is a theory of the history of prehistoric Ireland in the Iron Age put forward by the linguist T. F. O'Rahilly in 1946. It was based on his study of the influences on the Irish language and a critical analysis of Irish mythology. He distinguished four separate waves of Celtic invaders: * The Cruithne or Priteni (c. 700 – 500 BC) * The Builg or Érainn/Iverni (c. 500 BC) * The Laigin, Fir Domnann and Gálioin (c. 300 BC) * The Goidels or Gaels (c. 100 BC)