Doyle, never found as O'Doyle in modern times, stands high in the list of Irish surnames arranged in order of numerical strenght, holding twelfth place with approximately 21,000 souls out of a population of something less than 4 1/2 millions. Though now widely distributed it was always most closely associated with the counties of south-east Leinster (Wicklow, Wexford and Carlow) in which it is chiefly found to-day, as it is in the records of the fifteenth, sixteenth and seventeenth centuries.

The statement that the name is derived from the Irish word doilbh (which means dark, gloomy, melancholy) may be discounted: it is generally accepted that the correct derivation is dubh-ghall, i.e. dark foreigner, and the name in Irish is always written " Dubhghaill. As Dubhghall it appears in the "Annals of the Four Masters" as various dates between 978 and 1013. The family is not included in the great Gaelic genealogies, which supports the traditional belief that the eponymous ancestor is in this case a descendant of one of the Norsemen who settled in Ireland in pre-Norman times: and the fact that Doyles are and were always more numerous in areas adjacent to the sea coast, where Norse settlements existed, tends to confirm this view. Dughghall, it may be mentioned, is the word used in early times to denote a Norseman or Scandinavian. One authority, however, Rev. John Francis Shearman, asserts that the eponymous ancestor of the east Leinster Doyle was Dughgilla, son of Bruadar, King of Idrone (Co. Carlow) in 851.

There is reason to beleive that at the time surnames came into being in Ireland, that is to say for the most part the eleventh and twelfth centuries, more than one quite distinct family acquired that of O Dubhghaill or Doyle. It should be added that there is no reliable evidence for the claim which is sometimes made that some Doyles are offshoot of the great Decies sept of O'Phelan.

The first bridge built over the Liffey in Dublin was constructed by an O'Doyle. It was, however, in the nineteenth century that men of the name were particularly prominent, none more so than the famous "J.K.L." James Doyle (1786-1834), Bishop of Kildare and Leighlin, that champion of the Catholic cause. Another outstanding churchman was Father William Doyle, S.J. (1873-1917) : while the best known outside Ireland was undoubtedly Arthur Conan Doyle (1859-1930), the creator of Sherlock Holmes. His grandfather was Dublin born John Doyle (1797-1868), the famous "H.B." of Punch, who resigned his lucrative position on the staff of that well known weekly because of its anti-Catholic bias and it is worthy of National Biography, a distinction equalled by very few other families..