Tin is an essential metal in the creation of tin-bronzes, and its acquisition was an important part of ancient cultures from the Bronze Age onward. Its use began in the Middle East and the Balkans around 3000 BC. Tin is a relatively rare element in the Earth's crust, with about two parts per million (ppm), compared to iron with 50,000 ppm, copper with 70 ppm, lead with 16 ppm, arsenic with 5 ppm, silver with 0.1 ppm, and gold with 0.005 ppm. Ancient sources of tin were therefore rare, and the metal usually had to be traded over very long distances to meet demand in areas which lacked tin deposits.
Known sources of tin in ancient times include the southeastern tin belt that runs from Yunnan in China to the Malay Peninsula; Cornwall and Devon in Britain; Brittany in France; the border between Germany and the Czech Republic; Spain; Portugal; Italy; and central and South Africa.  Syria and Egypt have been suggested as minor sources of tin, but the archaeological evidence is inconclusive.