Cleary Ó Cléirigh, meaning "grandson of the scribe" is the Irish for both (O) Cle(a)ry and, in many cases in Ireland, Clarke. The surname is of great antiquity, deriving from Cléireach of Connacht, born c. 820, in turn descended from Guaire, a seventh-century king of Connacht. Cléireach derives from the same root as the English "cleric" and "clerk" and was used in the same way to describe both a priest and a scholar. Unusually, the anglcisation of the Irish name as Clark was actually quite accurate. The first of Cléireach’s descendants to use his name as part of a fixed hereditary surname was Tigherneach Ua Cléirigh, lord of Aidhne in south Co. Galway, whose death is recorded in the year 916. It seems likely that this is the oldest true surname recorded anywhere in Europe.