Recorded in both Scotland and Ireland in the spellings of McCloy, McCloye, and McLoy, this is a Gaelic surname. It is claimed to be a branch of the Clan Stuart of Bute. According to the famous Dictionary of Scottish Surnames by the late Professor Black of New York, the name derives from the same source as the surname 'Lewis'. This is from the pre 7th century 'Lughaidh'. This is quite probable as the very earliest charters state that '..one off the name called Lewis (and known in English as Fullerton) went to Arran where he was called McLewis, and later McCloy, holding crown lands there..' The date is uncertain but was about the year 1200. A later recording states that '..the most ancient family in Arran is by the natives (?) reckoned to be Mack Lowis..' The name is recorded as MacLow in 1511, and as M'Loy in 1526, with Donald MacCloye being a witness at Cowell in 1537, whilst Gilbert MacLoy was killed in the battle known as the 'Massacre at Toward' in 1646. This was an incident between the Clan Lamont and the Clan Campbell, in which the McCloys/McLoys supported the Lamonts. Other recordings include Donald M'Cloy in 1609 and his grandson also called Donald, who was appointed the bishop of Edinburgh in 1705, and later elected Primus of the Scottish Episcopal Church in 1720.