Kiley is an Anglicized form of the Old Gaelic "O' Cadhla". The Gaelic prefix "o" indicates "male descendant of", plus the byname "Cadhla" meaning graceful or beautiful; hence, "descendant(s) of the graceful one". This name is chiefly found in the Munster counties of Waterford, Limerick and Cork. The variant spelling Keeley appears in Counties Galway and Wicklow and Kealy is a County Kilkenny variant. The forms O' Quelly and Que(a)lly, recorded in Counties Clare and Waterford, in Petty's census, dated 1659 are accepted by Dr. Lynce in his "Cambrensis Eversus" as further Anglicizations of O' Cadhla - "O Cadhla sive (otherwise) Quaelly". However, another Gaelic name O' Caollaidhe containing the element "caol" meaning "slender" also gives rise to the Anglicized forms Queally and Queeley, which leads to confusion in tracing the exact source. Kiley is a very rare form of the surname, with Kiely being the more popular form of the name. The first recorded spelling of the family name is shown to be that of O' Cadhla, also called O' Dealy, of lar-Connaught, which was dated circa 1170 - Chieftain of Connemara, County Galway, during the reign of Rory O' Connor, High King of Ireland, 1166 - 1198. 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.