Chariots were used in Mesopotamia from before 3000 B.C. The earliest chariots had either two or four solid wheels. Chariots with spoked wheels were invented about 1900 B.C.
Early Sumerian chariots were pulled by donkeys. The charioteer steered the chariot using reins which went through a ring carried on the donkey's back and were attached to rings in their noses.