Ah, the wheel. The tool at the core of modern transportation, and so much more. The invention of the wheel has become a cultural trope, used to refer to prehistoric times, but did the wheel actually have an inventor?
We do have an "oldest wheel yet found." In 2002 Slovenian archaeologists uncovered a wooden wheel some 12 miles (20 km) southeast of Ljubljana. It was established that the wheel is between 5,100 and 5,350 years old. This makes it the oldest in the world used for transportation. A stone potter's wheel has been found at the Sumerian city of Ur, in modern-day Iraq, dated to about 3129 BC, and fragments of wheel-thrown pottery around 5,500 years old have also been discovered, evidence that the use of the wheel is even older — at least for pottery.
When was the wheel invented?
Who was the inventor of the wheel? Mesopotamian cultures are believed to have been the original inventors of wheels, though that premise is based solely on existing archaeological evidence. The Mesopotamian civilization used these early wheels for pottery creation. It was another 2,000 years or so before the Ancient Greeks developed the idea of the wheel enough to put them to use carrying loads.
The first wheels and axle carts designed by the early Greeks were very basic in construction. They essentially consisted of just two rods, with a wheel and an axle on the end. They could be used to carry large loads through fields.
Since the oldest known wheels date to around 3,500 BC, that means that their invention post-dates the invention of agriculture, boats, and woven cloth. From a period standpoint, this puts the invention of wheels sometime between the Neolithic and Bronze ages.
What is the importance of the wheel?
One reason why it may have taken so long to invent the wheel is that wheels and axles are not found in nature. Tools like levers or pitchforks are based on things that occur naturally, such as forked sticks. Although tumbleweeds and dung beetles use rolling, rolling is of little practical use without an axle.
The tricky thing about the wheel is not conceiving the notion of a cylinder rolling on its edge. It's figuring out how to connect a stable, stationary platform to that cylinder without impeding the cylinder's movement. Once early civilizations realized how much easier transportation would be with the wheel and axle, it becomes clear why the wheel was invented.
A closer look at the invention of the wheel and axle
In around 1975, archaeologists discovered the Bronocice pot, a ceramic vase uncovered in a Neolithic village in Poland. It is believed to date to between 3,635 and 3,370 B.C., and it features the earliest known depiction of what is likely a wheeled vehicle. If accurate, this means that the use of the wheel and axle may have first appeared somewhere in the Eurasian steppes. In fact, many words associated with wheels and wagons derive from the language of the Tripolye people, who lived in modern-day Ukraine.
The first carts with wheels and axles involved a fixed wheel and axle design, where the wheel and the axle turned together. Essentially, pegs were used to hold the wheel and axle in place, and all of the movement was done by this combined axle-wheel. It wasn't until later in wheel history that carts were designed which used holes, rather than pegs, to hold the axles in place.
This is harder because, in order to make a fixed axle with revolving wheels, the ends of the axle and the holes in the center of the wheels needed to be almost perfectly smooth and round. Otherwise, friction would prevent the wheels from turning.
The axles also had to fit snugly inside the holes in the wheels, but remain loose enough that they were free to rotate. This is why the development of the axle probably only took place after around 3,500 B.C. when the first copper chisels and gauges were created to allow the fine-fitted holes and axles to be chiseled.
At this point, the wheel had essentially evolved into what it is today, except that these wheels were made of wood and not of rubber and metal.
The modern wheel
Wheels today are practically nothing like early wheel designs. While they are, of course, still round, they are basically different in every other way. This is all due to innovations in material science and the development of mechanical engineering, allowing for more complex yet efficient wheel assemblies.
The invention of the wheel unlocked a wealth of other tools, including chariots, wheelbarrows, mills; as well as gears and a whole host of devices, from steamboats to bicycles and watches, that use gears.
The wheel and axle was one of the most important discoveries in human history. They were also one of the most difficult, requiring a number of different developments to occur almost simultaneously. In fact, the invention of the wheel and axle was so challenging that some archaeologists hypothesis that it probably only occurred once, in one place. From that place, it then spread so rapidly that today it is all but impossible to determine exactly where it originated.