wheel and axle

Circular frame or disc rotating on an axle. Early wheels probably evolved from log rollers used to aid the progress of a heavily laden sled or stone block, a slice of log attached solidly to an axle giving way to a crude disc wheel revolving on a fixed axle. Spokes were introduced about 2000 BC in Middle Eastern regions, an improvement that lightened the structure and provided levers to propel the vehicle when necessary.

In parts of the world where there were no draught animals, including North and South America, the wheel and axle never evolved, their use being introduced through European trade and settlement.

Most early disc wheels are found during the Bronze Age, but a Neolithic (New Stone Age) example discovered in the Netherlands indicates that metal tools were not required for their development or construction. In Britain nave bands, part of the construction of the wheel hub, have been uncovered from a late Bronze Age hoard in Heathery Burn Cave, Durham, northeastern England. The wheeled cart existed in Mesopotamia about 3000 BC, but did not occur in Egypt before 1600 BC.

Wheel-thrown pots are first found in Mesopotamia, although it is likely that the potter's wheel was invented before 3000 BC.