Which ancient Mesopotamian civilization is credited with developing the earliest known written legal code, predating Hammurabi's Code by several centuries?

In ancient Mesopotamian law, what specific type of property was protected by the principle that 'if a man's slave is injured by another man's slave, the owner of the injured slave receives compensation from the owner of the offending slave'?

Which ancient Mesopotamian civilization is credited with developing the earliest known form of a codified legal system, predating Hammurabi's code by centuries?