What metals is bronze made of?

The Bronze Age is a period in a civilization's development when the most advanced metalworking (at least in systematic and widespread use) consisted of techniques for smelting copper and tin from naturally occurring outcroppings of ore, and then alloying those metals in order to cast bronze. The Bronze Age is part of the three-age system for prehistoric societies. In that system, it follows the neolithic in some areas of the world. In many parts of sub-Saharan Africa, the neolithic is directly followed by the Iron Age.