This surname is of Medieval Irish origin and is, along with Conlan, synonymous with (O)Connellan, pronounced almost alike, with the spellings Conlon and Conlan being the more modern forms. Several different Irish surnames have been Anglicized as Conlon, the principal septs so called in English are, O'Conallain, of Roscommon and Galway, and O'Coinghiollain of County Sligo, with present day representatives found also in County Meath where they are sometimes called Quinlan, (O'Coindealbhain, in Irish), and descend from an important sept near Trim, which traces back to Laoghaire, King of Ireland circa 432. During the 17th Century the name was very numerous and widespread, and appears in seven variant spellings. One Robert Conlon, the infant son of Patrick and Elizabeth Conlan was christened on February 27th 1772 in Holborn, London. The first recorded spelling of the family name is shown to be that of Abraham O'Connellan (Archbishop), which was dated 1247, Armagh, Northern Ireland, during the reign of King Henry 111, 'The Frenchman', 1216-1272. 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.