Recorded in the myriad and contrasting spellings of Aleavy, Aleevy, Delea, Dunleavy, Dunsleve, and the patronymics MacDunlevy, McDunlevy, MacDunleavy, McDunleavy, with MacGlew, McGlew and McGlue, this is a surname of two claimed nationalities, but a single Gaelic origin. Whether Irish or Scottish, it is a much corrupted dialectal derivative of the ancient Mac Duinnshleibhe, meaning 'the son of Don of the mountain' or similar, from 'sliabh', a mountain. Most surnames of West Scotland are to be found in (mainly) Northern Ireland and vice versa, although sometimes, as with this surname, the spellings have strayed to a point where the relationship is not easy to understand. In the late medieval times, at a time of 'political correctness', many Gaelic surnames were 'exchanged' for anglicised or near English versions. In some cases these changes were based upon 'sounds like' transpositions. As examples the name Duibhghinn became Duffin, a straight sound swop, but Ghabhann became either Smith, because it actually means 'smith' or Gowan, a 'sounds like' form of Ghabhann. This surname is difficult to trace with exactitude. We can only repeat that the research of both the late Edward Lysaght for Ireland and Professor Black for Scotland came up independantly with the same results. Examples of the surname recording include James Dunsleve of Kintyre, who in 1310 received a land grants from King Robert, The Bruce, of Scotland, Cormac MacDonlevy circa 1460, who translated many medical works into Irish, Father Christopher Donlevy, who was martyrd in Ireland in 1644, Andrew McGlue, who married Mary Mullen at Bangor, County Down, on November 23rd 1813, and John McGlew, a witness at Antrim, County Antrim, on March 16th 1865.