In Mesopotamia we are not very sure of our dates at so early a period, nor have we got any clear evidence of the earliest copper civilisation of that region, but the beautiful copper lions brought back from Tell-el-’Obeid, near Ur, by Dr. H. R. Hall[92], show that at the time when they were made the art of working copper must long have been known, and Dr. Hall tells me that their date may be placed with fair certainty between 3500 and 3000 /B.C./ Small foundation figures, cast solid in copper, have been found which date from the time of Ur-Ninâ, about 3000 /B.C./[93], while Mr. Raphael Pumpelly, describing his excavations at Anau in Turkestan, states that he found copper implements in a deposit, which on other grounds he dates between 8000 and 7000 /B.C./[94] While there is no doubt that copper was found in the lowest layer of the Anau village site, there are few people who agree with the early date claimed for it by Mr. Pumpelly. Taking all the available evidence into consideration, it seems likely that copper was known and used in western Asia as early as 4500 /B.C./ and might conceivably have been known as early as 5000 /B.C./; that it was known before that seems unlikely as far as we can judge from the evidence available at present. Gold, as we have seen, seems to have been the first metal to be discovered, though we have no sufficient reason for believing that its discovery preceded that of copper by any considerable period. Objects of gold have been found in graves of the second pre-dynastic period in Egypt, as well as some of silver and of lead,[95] so that before 3500 /B.C./ the metal age had passed its infancy. It will be seen from what has gone before, that the discovery of metal must have taken place somewhere in western Asia; in Asia Minor, Armenia or Persia. The knowledge spread first of all from tribe to tribe and from city to city, and the objects were traded like the stone axes of Le Grand-Pressigny and Graig Llwyd; but about 4241 /B.C./ this knowledge was carried into Egypt with an invading people. So far, then, there is no evidence of organised trade, for the gold, silver and lead, which have been found in the pre-dynastic tombs, may have arrived in the same way. Gold, it is true, was found in quartz veins in the granite mountains by the shores of the Red Sea, and in the Wadi Foakhir,[96] but it is not clear that these sources were tapped before the fourth or fifth dynasties; in later days the principal source of supply was Nubia which had, however, been inaccessible to traders until Mernere had made the first cataract passable for navigation about 2570 /B.C./[97] Silver was always imported from abroad, probably from Cilicia.[98]