Recorded in a number of spellings including Kealy, Kealey, Keeley, Keely, Keiley, this is a surname of Irish or sometimes English, origins, and it is usually without a full genealogical study to decide which is which. If Irish, although often confused with the much more common Kelly, it in fact had a totally separate origin, being derived from the ancient medieval Gaelic name O' Caollaidhe, meaning the male descendant of the slim one! As to whom the 'slim one' was is unclear, but the majority of Gaelic surnames descend from a nickname for the original chief of the clan perhaps in the 13th century or earlier. However both in Ireland and England the name can also be a variant of the place name and surname Keighley, and hence is locational from the town of that name in the county of West Yorkshire. Keighley means the farm of Cyhha, a personal name of pre 7th century origins and uncertain meaning. Amongst the surname recordings is the christening of Henry, the son of Thomas and Thomasina Keely, on April 1st 1798 at the church of St. Clement Danes, Westminster, whilst in Ireland where most early records were destroyed by the IRA in 1922, we have that of William Keely, whose daughter Biddy, was christened at Tuam, County Galway, on June 30th 1864. One of the earliest recordings anywhere is that of Martha Keely. She was christened on June 11th 1563, at St. Peter's Cornhill, in the city of London, during the reign of Queen Elizabeth 1st, known as "Good Queen Bess", 1558 - 1603. Surnames became necessary when governments introduced personal taxation. In England this was sometimes known as the Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.