Now the importance of this passage is that it shows us that as early as 2800 /B.C./ the Babylonians were cognisant of the existence of tin, and doubtless aware of its value as an ingredient of bronze; this can only mean that they were using it to harden the copper, which they had worked so well centuries earlier. The passage implies that Sargon’s rule extended to Ku-Ki, which may perhaps mean no more than that some of his subjects had a trading post there. What seems important is that the discovery of the value of tin and bronze had been made before 2800 /B.C./, somewhere in western Asia, though at what sites is at present uncertain. Copper mines, which are known to have been worked at an early date, exist south of Trebizonde, near Erzeroum, in Armenia and at Diarbekir in the upper valley of the Tigris; ancient tin workings have been found further east in Khorazan.[100] But the local supply of tin was apparently insufficient, and merchants from the Persian Gulf were carrying on a trade in this commodity with a place in the Mediterranean region, even if they had not already, as seems probable, established a definite trading post in Ku-Ki. Thus we see that a definite organised trade, both by sea and by land, had been established in the eastern Mediterranean region before 2800 /B.C./, and that this included a new and important feature, the search for and importation of raw materials as well as the export of manufactured articles. Now, as I have shown elsewhere,[101] at a date which cannot be very much later, during a period which closed about 2200 /B.C./, the eastern Mediterranean was in close trade relations with Spain, and was exploiting the mineral resources of that peninsula. At present it is uncertain who these traders were, but they seem to have been in touch with Crete, the Cyclades and the second city of Hissarlik, and perhaps too with Cyprus. Though we have no evidence that these traders were from the Persian Gulf, they were trading between Spain and the area in which Ku-Ki probably lay, and if they were not subjects of the Babylonian Empire, they were at least carrying on the metal trade first organised by the people from the Persian Gulf. Quite recently it has been stated that there is no clear evidence that the Spanish copper mines had been worked at so early a time,[102] but the data cited by Siret[103] seem to me to prove conclusively that the early settlements of El Argar had direct or indirect trade relations with Hissarlik II., and the discovery throughout the Spanish peninsula of clay balls of a certain type,[104] which exactly resemble some found by Schliemann in the burnt city,[105] seems to me to place this early connection beyond all reasonable doubt.