I do not know about the Matchett's, however the Norman's ie. William I of England brought many French Nobles to England with him from Normandy and therefore, many French names. During the reign of King Henry of England and Elenor of Aquitane, there was a big push into Ireland by these same noble French families now in England. At one time, King Henry gave control of these nobles to son John Lackland (yes, of Robinhood fame)and therefore Ireland. This is the time period when the Norman French prefix "Fitz" Meaning "son of" became attached to many irish names, such as Fitzpatrick, Fitzgerald, etc. This conquest brought a major influx of French names to Ireland that are still common today.