Discusses the occurence of metallic iron in ancient copper and presents probable explanation of the many thousands of chemical or spectrochemical analyses of ancient copper, principally from central and northern Europe, only a few report in excess of 1% and of these the iron occurs in iron age metal. On the other hand, some recent articles report much higher iron. These high-iron coppers are from Sardinia, Greece, Israel, Egypt and India and range in date from the chalcolithic and Early Bronze age through the iron age. It is proposed, that the iron was introduced as a result of simultaneous reduction of iron oxides in the furnace burden to solid metallic iron during the copper smelting operation.