This name, with variant spellings Dunmuir, Dunsmore, Dunsmuir, Dunsmure and Dinsmore is of Scottish territorial origin from the old lands of Dundemore near Lindores, Fife. The component elements of the placename are believed to be the Old Gaelic "dun(dh)", a fort plus "mor", big or extensive. In 1248, Henry de Dundemore, (see below), made a controversy with the monks of Lindores concerning the service in the chapel of Dundemor, and circa 1250, he witnessed the gift of one piece of silver annually to the monastery of Arbroath, formerly called Aberbrothock. Sir John de Dundemore was a regent during the reign of Alexander 111, (1249-1286), and a Patrick de Dundemer of Fifeshire rendered homage in 1296. One Richard de Dunmore was juror on an inquest at Perth in 1305, and Lord Charles Murray, (1660-1710), was created first Earl of Dunmore in 1686. The first recorded spelling of the family name is shown to be that of Henry de Dundemore, charter witness, which was dated circa 1219, in the "The Register of Arbroath Abbey", during the reign of King Alexander 11 of Scotland, 1214 - 1249. 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.