Double-barrelled surnames, usually created following a marriage between two families, have no overall meaning as a unit, but the separate parts have their own history and derivation. In this instance, the name D'Abbot is of French occupational origin for a worker in an abattoir, from "abattre", to slay, slaughter. Job-descriptive surnames riginally denoted the actual occupation of the namebearer, and later became hereditary. On June 5th 1671, Dominique, son of Josephe and Marie D'Abbat, was christened in Gerbeville, Meurthe-et-Moselle, France, and on May 2nd 1702, Claude Dabot and Marie Guillaume were married at Vallois, Meurthe-et-Moselle. Doyle is one of the most ancient names of Ireland, and also one of the most numerous, being twelfth in the table of numerical strength of Irish surnames. The Gaelic form of the name "O'Dubhghall", translates as "male descendant of Dubhghall", a byname meaning "dark stranger". There is a traditional belief that the ancestor of the O'Doyles was a descendant of one of the Norsemen who settled in Ireland in pre-Norman times, though others claim that Dubhgilla, son of Bruadar, King of Idrone (Co. Carlow), in 851, is their ancestor. The surname is most widespread in south-east Leinster, and probably the best known bearer of the name is Arthur Conan Doyle (1859 - 1930), the creator of Sherlock Holmes. The first recorded spelling of the family name is shown to be that of O'Dubhghaill, which was dated 978, in the "Annals of the Four Masters", during the reign of Brian Boru, High King of Ireland, 940 - 1014. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.