Clery, often spelt Cleary, is one of the Gaelic Irish surnames which has kept the prefix O to some extent in modern times. O'Clery is O Cleirigh in Irish probably derived from the work Cleireach meaning a clerk or cleric. The name itself means descendant of Cleireach, who was of the line of the famous Guaire the Hospitable, King of Connacht. Cleireach was born about the year 820 A.D. some two centuries before hereditary names began to be generally used. That of O'Clery, however, was one of the earliest recorded surnames: it dates from the middle of the tenth century. The O'Clerys were the chief family in that part of the present Co. Galway which is covered by the diocese of Kilmacduagh, but their influence gradually declined and by the middle of the thirteenth century they had been driven out of their original territory and settled elsewhere. By far the most important of these branches was that which domiciled in Counties Donegal and Derry: many of its members distinguished themselves as poets and antiquarians there. Since the Plantation of Ulster in the seventeenth century, and the consequent anglicization of what was formerly the most Irish of the Four Provinces, the common English surname Clarke has been very widely substituted for O'Clery there, and also indeed elsewhere in Ireland. Without a reliable pedigree or at least a strong family tradition it is therefore impossible to say whether an Irish Clarke is an O'Clery in disguise or the descendant of an English settler; but it is probable that most of our Clarkes are in fact O'Clerys. The branch which settled in Co. Cavan has almost disappeared (at least as Clery, though Clarke is fairly common to-day in Co. Cavan), but the third, which went to Co. Kilkenny, is still to be found in considerable numbers if not actually in Co. Kilkenny, in the adjacent counties of Tipperary and Waterford. Clery and Cleary are also found as variants of Clerkin (O Cleirchin) a sept located in the barony of Coshma, Co. Limerick. Clarke, with an estimated population of over 14,000 persons comes as high as thirty-second in the list of the hundred commonest surnames in Ireland (this of course includes all persons of the name whether their origin be Irish or English). Clery (including Cleary, O'Clery and O'Cleary) musters some 5,000 persons. The O'Clerys of the seventeenth century who left their mark on the literary history of Ireland are too numerous to mention individually. The most famous were Michael, his brother Conary and their cousin Cucoigchriche (sons of Lughaigh O'Clery the chieftain and historian), who with Fearfasa O'Mulconry compiled the "Annals of the Four Masters" which was finished in 1636. A modern historian of the name was Arthur Patrick O'Clery (1841-1915), born at Kilkenny, the missionary to Irish and Scots soldiers in the Low Countries; Dr. Joseph Clarke (1758-1834), the Derryman who did so much for the Rotunda Hospital, Dublin; and in our own time Thomas Clarke (1857-1916), first signatory to the republican proclamation in 1916 who was executed after the Easter Week Rising. Two sisters, Julie Cleary and Desiree Cleary (1781-1860), daughters of an Irish merchant in Marseilles, became respectively Queens of Spain and Sweden under Napoleon. There is another Gaelic surname which has become Clery in English in some places, though more usually MacCleary or MacAlary. this is MacGiolla Arraith, a branch of the O'Haras, who went with them to Co. Antrim and became established there. For O'Clery pedigrees see The Tribes and Customs of Hy Fiachrach, Appendix C.