First part of the Bronze Age .
The beginning of the period is sometimes called the Chalcolithic (Copper-Stone) Age (с 8000 BC), referring to the initial use of copper ore. Sometime after 6000 BC, smelting ore to produce pure copper was discovered in Anatolia (Turkey). From 5000 BC copper metallurgy, with cast tools and weapons, was a factor leading to urbanization in Egypt and Mesopotamia. Copper metallurgy spread to India by 3500 BC and to Europe and China by 3000 BC. Copper ore occasionally contains tin, which makes dating bronze metallurgy difficult. The Bronze Age began с 3500 BC in the Middle East and spread throughout the Old World between 3000 and 1800 BC. The Copper Age began in the New World с AD 100 and the Bronze Age с 1000.