Copper was one of the first metals widely used by humans, due to its malleability and durability. Like gold and silver, it could be melted and cast into many shapes. But copper proved to be a stronger material and quickly became the preferred medium for making tools, including weapons. Copper-headed maces were first cast in Mesopotamia in the third millennium BC. Some weapons, however, did not immediately make the transition from stone to metal. Bowmen continued to use stone arrowheads throughout the Copper and into the Bronze Age, due to their cheaper production costs.

At the start of the Copper Age, the Egyptians were already constructing warships out of bundles of reeds. Such vessels were essentially rafts, suited for duty only on the relatively calm waters of the Nile. By 2000 BC, both Egypt and Crete were building wooden ships capable of navigating the choppy, wind-swept waters of the Mediterranean. For propulsion, these warships used a combination of a square sail (for speed) and oars (for maneuverability).

Another defining phenomenon of this period was the explosion of agriculture. The ability to farm enabled people to settle in one area, which was a necessary condition for the emergence of civilization. The first civilization arose in Sumer in the Euphrates River valley. In addition to growing crops like barley, wheat and grapes, the Sumerians domesticated animals for meat and other materials as well as to provide power for plows and carts. For their carts, they fashioned the first wheels by fastening rounded wooden boards together. Lists of farm commodities, and related records like horse lineages, were recorded on clay tablets using cuneiform, the first system of writing. By the end of the Copper Age, agriculture had spread from the Middle East through all of Europe.