Final answer:
Ur-Nammu founded the Third Dynasty of Ur around 2050 BCE, known for its advanced bureaucracy and law code, and played a significant role in unifying the Mesopotamian city-states into an empire.
Step-by-step explanation:
The person who founded the Third Dynasty of Ur around 2050 BCE was Ur-Nammu. This dynasty, also known as Ur III, followed the preexisting Akkadian and Sumerian city-states, and Ur-Nammu is credited with unifying these cities under his control, forming a significant empire. Moreover, Ur-Nammu was known for implementing an advanced bureaucracy and for publishing a law code, elements which played crucial roles in the administration of his empire. The Third Dynasty of Ur was an example of an early bureaucratic state, demonstrating the continuity of Mesopotamian civilization through various empires including the Akkadian, Babylonian, and Sumerian.