What are the 5 Sumerian social classes in western civilization?

The ancient Sumerians did not have a five-tiered social class structure. However, they did have a stratified society with three main classes: the upper class, the middle class, and the lower class.

The upper class was made up of the king, his family and court, and the wealthy merchants and landowners. The middle class was made up of artisans, shopkeepers, and farmers. The lower class was made up of laborers and slaves.