This ancient name is of Celtic origin, and is a locational surname deriving from any of the places called Carthew in Cornwall, in the parishes of St. Issey, St. Austell, Wendron and Madron, or from Cardew in Cumberland, near Dalston. All of these places are named with the ancient Celtic elements "ker", fort, camp, earthwork, and "du", dark, black; the latter being changed by the typically Celtic initial mutation of "d" to "dh", giving a "th" sound. Carthew in St. Austell is recorded as "Carduf" n 1327, the "f" being an archaic spelling, and as "Carthu" in 1367. Locational surnames were acquired by the lord of the manor, and local landowners, and were used particularly as a means of identification by those who left their birthplace to settle elsewhere. Among the recordings of the surname in Church Registers are those of the christening of Benett, son of John Carthew, at St. Columb Minor, Cornwall, on June 16th 1564, and of John, son of Thomas Carthew, on January 1st 1697, at St. Bride's, Fleet Street, London. One Thomas Carthew (1657 - 1704) was a barrister of the Middle Temple, London, and became serjeant-at-law in 1700. A Coat of Arms granted to the Carthew family depicts a red chevron between three falcons proper on a gold shield. The Crest in a falcon rising gorged with a ducal coronet and belled, proper. The first recorded spelling of the family name is shown to be that of John de Carthew, which was dated 1332, in the "Subsidy Rolls of Cumberland", during the reign of King Edward 111, known as "The Father of the Navy", 1327 - 1377. 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.