Recorded in several forms including Roy, Milroy and Mulroy, this is a Gaelic surname. It derives from the old Scottish surname MacIlleruaidh or Mac gille Ruaidh meaning 'The son of the red haired lad'. Gaelic surnames are nearly always patronymics and derive from a nickname for the original chief of the clan. In this case the name may be ethnic, and have referred to an Anglo-Saxon as they often had red hair. It is said that the the surname was first recorded in the medieval period with early recordings including Donald M'Gilleroi, a notary public in 1465, and Ade M' Gilroy, a tenant of Eglisdisdane and Balnegreagane. These are recorded in the Exchequer Rolls of Scotland, in 1480. Milroy, from M' Ilroy with omission of the apostrophe, is widespread in Ayrshire and Wigtownshire, whilst as Malrie, Malroy, Milrie, Milroy and Mulroy, they were all recorded in Wigtownshire and Minnigaff in 1684. John Milroy in Fintallock, Penninghame, a Covenanter, was hanged at Wigtown in 1685 and others of the name were obliged to flee from religious persecution. The surname is also found in the abbreviated form Roy. The earliest known recording is proably that of Michael M'Gilrey, a tenant of Thornhill, Dumfriesshire, which was dated 1376. This is in the Ancient charters of the earldom of Morton, during the reign of King Robert 11 of Scotland, 1371 - 1390. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.