The Bronze Age is the time period when people made tools from an alloy (a mixture of metals) called bronze. It started after the Stone Age. Bronze is a mixture of mainly copper and tin: usually nine parts copper to one part tin. Materials like wood and stone were also used for tools, but bronze was better for cutting and chopping, and was easy to shape. The Bronze Age was not at the same time everywhere, because different groups of people began to use bronze at different times. In Western Europe, the Bronze Age lasted from about 2000 BC until 800 BC. In the Middle East, it started about a thousand years earlier. For example, bronze was first used in Mesopotamia around 3300 BC.