Double-barrelled surnames, usually created following a marriage between two families, have no overall meaning as a unit, but the separate parts have their own meaning and derivation. In this instance, the name Campbell is of medieval Scottish origin, deriving from the Gaelic "cam", crooked, arched, with "beal", mouth, and was originally given as a nickname to some early chief of the clan distinguished by this physical feature. Gillespic Cambel, noted in the 1263 Exchequer Rolls of Scotland, is the earliest recorded bearer of the surname. One, Duncan Campbell, who witnessed a charter by Duncan, Earl of Levenax, circa 1390, is believed to be the first to introduce a "p" into the name, influenced by the erroneous theory that "Cam(p)bell" comes from the Norman French "de Campobello", "of the beautiful plain". Dunlop is also of medieval Scottish origin, and is a locational name from the lands of Dunlop in the district of Cunningham, so called from the Gaelic "dun", fort, and "lapach", muddy. Constantyn Dunlop of Cunningham appears on record in 1496. The surname is now widespread in Ayrshire, and a notable namebearer was James Dunlop, (deceased 1832), of Dunlop, Ayrshire, created lieutenant-general in 1817 following a distinguished military career in Nova Scotia and Halifax. The first recorded spelling of the family name is shown to be that of Willelmus de Dunlop, which was dated 1260, in the "Records of the Royal Burgh of Irvine", during the reign of King Alexander 111 of Scotland, 1249 - 1286. 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.