Artisans of Sumer, in the Tigris-Euphrates valley, develop around 3500-3300 BC the deliberate alloying of copper with tin to produce bronze, the first functional metal alloy in history. Bronze, harder and stronger than pure copper, transforms the manufacture of tools, weapons, and ritual objects, and gives its name to the Bronze Age in the Near East. Tin, a scarce mineral in Mesopotamia, had to be imported through extensive trade networks reaching as far as Afghanistan, which made control of these routes a decisive economic and political factor throughout the period. This innovation precedes Hittite iron by roughly 1,700 years and represents the starting point of all subsequent alloy metallurgy.