The alloy bronze, containing copper and tin, was probably made by melting together the separate metals. It was in use in a very ancient period in Egypt and in Mesopotamia. Recent discoveries at Ur seem to indicate that bronze rich in tin was in use by the Sumarians before the Egyptians, but its use diminished after the very early period, when the alloy was replaced by one of copper with lead an antimony. Linguistic and pictorial evidence suggests that the Egyptians and Sumerians, unlike the Jews, Greeks and Romans, had separate names for copper and bronze, and that they also had names for the metal tin. Possible sources for the copper and tin of ancient bronzes are considered. The source of the tin in the period 3500 B.C. is a difficult problem, but the most probable hypothesis is that the tin was obtained in Dragiana, in Iran (Persia), and it is possible, in view of the similarity between the Sumerian civilization and that of Mohonjo-daro in the Indus Valley, that the invention of bronze itself was made in this region of Iran, where the Sumerians became acquainted with it in their migration to Mesopotamia, and through them knowledge of bronze spread to the rest of the ancient world.