Presurnames

• before surnames: in Irish history before the 10th century, people were generally known by their patronymics, denoting their father's name (e.g. mac Néill = Niall's son) or their grandfather's name (e.g. Ó Néill = Niall's grandson); from around the 10th century surnames of a similar construction came into use, so a man called mac Néill was not necessarily the son of a man called Niall