The territory of the O'hEachtighearna sept was in south-eastern Clare, in the Barony of Bunratty Lower, around Sixmilebridge, whence at the end of the Gaelic period they moved southwards into County Limerick and County Cork where this name is principally found. The maritime county of Cork, in Munster, is bounded by the sea on the south-west, the south and the south-east. To the east it has land boundaries with the counties of Waterford and Tipperary, and to the north with Limerick and to the west with Kerry. Anciently the country formed part of the kingdom of Desmond. After the Anglo-Norman Invasion the whole of the present county, save the City of Cork (which had been founded by the Vikings) and its surroundings, was granted in 1177 by Henry II to Anglo-Norman knights who brought over their followers and established a military colony. The name was originally occupational 'an owner and breeder of horses'. Ireland was one of the earliest Countries to evolve a system of hereditary surnames: they came into being fairly generally in the 11th century, and indeed a few were formed before the year 1000. In County Waterford the English name HEARN is a synonym of AHERN and AHERNE. When the sparse Irish population began to increase it became necessary to broaden the base of personal identification by moving from single names to a more definite nomenclature. The prefix MAC was given to the father's christian name, or O to that of a grandfather or even earlier ancestor. A notable member of the name, under the spelling of AHERNE, was Brian Aherne (1902-86) who was an English born Hollywood film star specializing in the 'gentleman-cad' roles. He was born in King's Norton, Worcestershire. After London stage appearances and American film roles he went on to receive an Oscar nomination for his role as the Emperor Maximilian in "Juarez" (1939). Between the 11th and 15th centuries it became customary for surnames to be assumed in Europe, but they were not commonplace in England or Scotland before the Norman Conquest of 1066. They are to be found in the Domesday Book of 1086. Those of gentler blood assumed surnames at this time, but it was not until the reign of Edward II (1327-1377) that it became common practice for all people.