Possibly the swiftest route to your roots.
Irish genealogy website directory.
www.rootsweb.ancestry.com/~irlkik/kfamily.htm
Description:
It was not until the reign of Edward I, or about the year 1300, that surnames began to be fixed. From that period, Fitzgerald, Butler, Fitzmaurice, Grace, etc., begin to be accepted as surnames, replacing such designations as John Fitz Thomas, Theobald Fitz Walter, Oliver Fitz William, etc. Somewhere along in that period also, these names begin to appear in their Irish equivalent.
