This name is an Anglicized form of the old Gaelic Mac Ceadaigh. The Gaelic prefix "mac" means "son of ", plus the personal byname Ceadach from "Cead", hundred, and originally given as a nickname to one who claimed to have fought in a hundred battles. Conn Cead Cathaing i.e. Conn of the Hundred Battles, a 4th Century High King of Ireland, is a remote ancestor. The name Ceadach was also popular with the great O' Mores, leading sept of the "Seven Septs of Leix", with whom the McKeadys were closely associated. The Leinster M(a)cKeadys were followers of the Irish rebel Rory O' More who commanded the Irish forces of Leix and Offaly in the risings of 1641 and 1643. Another branch of the sept were located in Connacht and the name appears both as MacKeady and O' Keddy in the 16th Century Fiants Records of Co. Galway, however, by 1793 only the form Keady was recorded in the parish of Moycullen, Co. Galway. Keady is also the name of a leading Corca Laoidhe (South-West Cork) sept whose name is written as MacCeidigh in the Gaelic. The first recorded spelling of the family name is shown to be that of MacKeady, which was dated circa 1558, "Elizabethan Fiants Records" of Leix, during the reign of Queen Elizabeth 1, "Good Queen Bess", 1558 - 1603. 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.