This unusual surname, recorded in Church Registers of Scotland and Ulster from the mid 17th Century, under the variant spellings McElhone, McIlone, McIlhoan, McCalin and McAllen, has two distinct possible sources, each with its own history and derivation. Firstly, McIlhone may be of early medieval Scottish origin, and a late variant of the urname M(a)cAllan, itself an Anglicized form of the Old Gaelic "MacAilin", son of Ailin, a Celtic male given name of great antiquity and obscurity, ultimately believed to derive from a British (pre-Roman) word meaning "harmony", but in Gaelic countries, it is interpreted as "Rock", from the Old Gaelic "ail", rock. One Gilfelan M'Allan was among several others recorded at the Stirling Assizes in 1477, and John McCallane was a tenant of Drumnamark, Ardmanoch, in 1504. The second possibility is that McIlhone is indigenous to Ulster, and an Anglicization of the Old Gaelic "Mac GiollaComhghain", son of the attendant of Comhghan, from "Mac", son of, "giolla", attendant, man-servant, and the male given name "Comhghan". On January 22nd 1658, John, son of Brian McIlone, was christened at Derry Cathedral, Londonderry, and on December 27th 1713, William McIlhone and Catherine Maginnity were married at Downpatrick, County Down. The birth of James, son of John McIlhone and Isabella Campbell, was recorded in Edinburgh, Midlothian, on May 5th 1874. The first recorded spelling of the family name is shown to be that of Dungall M'Alayne, which was dated 1376, in "Ancient Charters of the Earldom of Morton", during the reign of King Robert 11 of Scotland, 1371 - 1390. 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.