Until the 10th century people had no family name. they lived in small villages and had a first name to identify them from one and other. Ireland is thought to be one of the first countries to begin to use Surnames.
The process of adopting surnames started earlier in some areas, while in others it started later and in some places continued even down to the 19th century. While it was the norm in Europe in the 11th century that people were without surnames, by the 15th century it was the norm that they did possess them.
As villages got bigger there might be two Pauls or three Johns and thus additional "family" names were invented to distinguish them and allow taxes etc to be collected.
There were several ways of creating a surname or family name.
- From the occupation of the family, e.g. John the Baker.
- From the father's name. In Irish Mac means Son of
- From the "Clan" where in Ireland O' means Grandson of, or member of the clan of
- From the place the family lives, e.g. Field or Lake.
- From religious connections.
In 10th century Ireland the influence of the Catholic church was important in creating surnames.
In particular those beginning with "Gil-" or "Kil-", an anglicised version of the Irish Giolla, meant follower or devotee. Normally it was a follower of a Saint or an important Leader. For example, Gilmartin (in Irish Mac Giolla Mhairtin), means "son of a follower of (St.) Martin" and In Irish Giolla Caoch means "a follower of Caoch".
The origin of Caoch" is still being researched but has been seen in use in this context as "the blind" in many Irish Genealogical studies.
Thus the surnames Kilky, Kilkie, Kilkey, Gilkie and Gilky are derived from the 10th century Irish "Mac Giolla Caoch" and the name means Son of a follower of "The Blind".