Recorded in several spellings including Maguire, MacGuire, McGuire, and even Macquire, this is a famous Irish surname. It derives from the pre 10th century Gaelic "MagUidhir". The prefix "Mac" written as "mag" before a vowel means "son of", with the personal byname "Uidhir", the genitive of "odhar", dun-coloured. Traditionally, Irish family names are taken from the heads of tribes, revered elders, or some illustrious warrior, and are usually prefixed by "Mac, Mag", son of, or "O", denoting "grandson, male descendant of". The great MagUidhir sept belonged to the Ulster county of Fermanagh, and their stronghold was on Lough Erne where they were Barons of Enniskillen. The MagUidhir chiefs were among the most important in the Province of Ulster, having influential associations with the kingly O'Neills and the princely O'Connells. In 1598, the most noteworthy of their chiefs, Hugh Maguire, commanded the victorious Irish cavalry at the Battle of the Yellow Ford. Distinguished bearers of the name throughout history include: Nicholas Maguire (1460 - 1512), bishop of Leighlin; Connor Maguire, second Baron of Enniskillen (1616 - 1645); and Thomas Maguire (1831 - 1889), professor of classical composition, Trinity College, Dublin, 1880. A Coat of Arms granted to the Maguire family is a green shield with a white horse fully caparisoned, thereon a knight in complete armour, on his helmet a plume of ostrich feathers, and his right hand brandishing a sword all proper. The first recorded spelling of the family name is shown to be that of MagUidhir, which was dated 956, in "Ancient Annals of Ulster", during the reign of Brian Boru, High King of Ireland, 940 - 1014. Surnames became necessary when governments introduced personal taxation. In England this was known as Poll Tax. Throughout the centuries, surnames in every country have continued to "develop" often leading to astonishing variants of the original spelling.