More than 4,500 years ago, well-to-do Sumerians were wheeling around Ur in donkey-powered carts and chariots. Whether or not their civilization ever reached the point where wives demanded chariots of their own for shopping is not known, but archeologists believe that the Sumerians were among the first to possess wheels and wheeled vehicles.
No one knows exactly when or how the wheel itself was first used, except that one day long ago a perceptive man saw that a disk is capable of turning on a central axis. It's fairly certain that he didn't sit down at that moment and formulate any laws of physics, but his first wheel did just what all wheels since have done: it lessened the friction between an object and the surface beneath it and thereby made it much easier to move the object along. The importance of the wheel's discovery was such that no historian would be far wrong in claiming that the world began moving toward its present civilization on Sumerian wheels.
The Sumerians settled on the Plain of Shinar, near the mouths of the Tigris and Euphrates Rivers, after migrating from the north. The plain is part of what is known as the Fertile Crescent, the northern end of the Arabian Peninsula, which was to cradle such famous cities as Damascus, Nineveh, Babylon, Kish and the earliest of all—Ur.
At Ur, scholars learned much about the Sumerians and what their city must have been like. Remains of their writing system reveal that these amazing people farmed irrigated fields of barley and wheat, used copper for tools and weapons, and traded with far-away peoples in metals, cattle and cloth, as well as developing wheeled vehicles. All of this happened thousands of years before Columbus set sail.
Fragments of ancient cultures indicate that the first wheels were probably developed in logical steps. From rollers or logs, which were very likely the first wheel-like devices, solid wheels evolved, which were little more than chunks of round tree trunks on a fixed axle. After centuries of bumping and wobbling on the massive, solid wheels, the hub and spokes were introduced, making it possible to construct wheels in sections. As wheels turned faster, they wore faster and became lopsided. Metal came into common use to sheath the axle from the grinding wear of wheel action; then "tires" of wood or copper were devised to stand up better under the rigors of travel.
Finer touches were added later. Assyrian wheels were studded with nailheads about 720 B.C., giving the wooden rims a longer life. As men rode further afield, they sought relief from the jounce of their vehicles, and they discovered that the higher the wheel, the easier the ride over rough ground. Although Chaldeans 1500 years before had used four wheels on their war chariots, the Persians of 450 B.C. are credited with the first real four-wheeled carriage. Their haramaxa not only distributed the weight of loads better but was also a boon to passenger comfort. The Greeks introduced wheels of bronze, and the Romans, in keeping with their paved city streets and fine road systems, made great progress in improving the wheel.
With the Greeks and Romans came recorded history, and the use of the wheel is thereafter a well-chronicled story of further applications and refinements. In fact, the wheel became so much a part of everyday life that people soon forgot its origin in the Middle East, where a Sumerian put together a contrivance of wood or stone and, finding that it would roll along quite nicely, decided that it might be a handy thing to have around.