Recorded in several forms including Cardew, Carthew, Cardy, and sometimes Cardow, Cardo and Cardoe, this is a complex English surname. It is usually considered to be locational in origin from the villages called Cardew in the parishes of Trevalga and Warbstow in Cornwall, although there is also a place called Cardew in Northumberland, which may have given rise to the surname. All these places have the same meaning of the "Dark fortress", from the pre 7th Celtic words "ker" meaning a fort, and "du", a dark place. It is also possible that the name is topographical from the Olde French words "carde" or the earlier Latin "carduus". These described a special thistle used in the carding or teasing of wool, to clean it before the spinning process, and hence they described a person who lived by or worked on these thistle beds. Finally it is also possible that the name may have been a medieval nickname for somebody who was a prickly character, or given the riobust humour of the Middle Ages, the complete reverse! Early examples of the surname recordings taken from the early surviving church registers of the diocese of Greater London include Robert Cardo at St Mary's Bermondsey, on April 19th 1559, and Robert Cardew, who married Ann Harte at St James Clerkenwell, on August 1st 1602.