Norman Irish surnames

In May 1169 a force of Anglo-Norman mercenaries landed in Ireland at the invitation of Diarmait Mac Murchada, the deposed king of Leinster, who wanted his kingdom back. Within a century their families held land across Leinster and Munster, and their names are still the commonest non-Gaelic surnames in the country. You can read the Norman-French in them. Fitz is fils, son, Fitzgerald, Fitzgibbon. De is of, and usually of a place — de Búrca (Burke), de Paor (Power), de Róiste (Roche). Butler was the king's butler.

The striking thing is how fast they went native. The phrase for it, coined later, was that they became more Irish than the Irish themselves: they married into Gaelic families, spoke Irish, kept Irish poets and Irish law, and some took Gaelic patronymics of their own. The Costellos are Mac Oisdealbhaigh, the sons of Oisdealbh; the Berminghams became Mac Fheorais, the sons of Piers; the Jennings are Mac Sheóinín, little John's people. Laws passed at Kilkenny in 1366 tried to forbid the Irish language and Irish dress to the colonists. They did not work.

A good many of the invaders were not from Normandy at all but from the Norman lordships of south Wales, and Flanders sent a contingent too — Prendergast and Fleming carry that in their names. The largest single reminder is Walsh, Breathnach, which simply means the Welshman and is the fourth most common surname in Ireland. Their descendants in the walled towns and the Pale around Dublin became the Old English, Catholic and self-consciously loyal, until the Reformation of the sixteenth century set them apart from the Crown and eventually cost them their land.

Sources: Wikipedia — Norman invasion of Ireland ↗ · Wikipedia — Old English (Ireland) ↗ · Wikipedia — Walsh (surname) ↗

Homelands are the historic heartland of the name, not where the family is now — people moved, and the Famine and the plantations moved them further.