The Jemdet Nasr Period took place in southern Mesopotamia with a great number of administrative cuneiform tablets and seals coming from this area. The stamp seal was a carved object, usually made of stone, which first appeared in the fourth millennium BC and was used to impress pictures or descriptions into soft, prepared clay. These seals guaranteed the authenticity of marked ownership: as such, they were instrumental in legal transactions, and in the protection of goods against theft. Seal amulets with stylised animals have been found throughout Mesopotamia in contexts dating to the late fourth millennium BC, although stamp seals and cylinder seals were the predominant types in the ancient Near East.
For more about stamp seals, see our relevant blog post: Making their Mark