Sumerian job specializations include craftsmen, artisans and priests. The advent of job specializations is the result of a surplus of food and population growth. Since everyone did not have to work on farms anymore, they were able to seek out other ways to earn money.
The primary artisan specialization was pottery. Craftsman specialization include stone cutters, metal smiths, fisherman, weavers, sailors, bricklayers, farmers, shepherds and leather-workers. They invented the wheel to make their chariots and carts more mobile and to expand their ability to make pottery. They started to smelt iron and they used seals for the purpose of stamping clay with a carved insignia.