The Third Dynasty of Ur, also called the Neo-Sumerian Empire, refers to a 22nd to 21st century BC (middle chronology) Sumerian ruling dynasty based in the city of Ur and a short-lived territorial-political state which some historians consider to have been a nascent empire.
The Third Dynasty of Ur is commonly abbreviated as Ur III by historians studying the period. It is numbered in reference to previous dynasties, such as the First Dynasty of Ur (26-25th century BCE), but it seems the once supposed Second Dynasty of Ur never existed.
The Third Dynasty of Ur was the last Sumerian dynasty which came to preeminent power in Mesopotamia. It began after several centuries of control by Akkadian and Gutian kings. It controlled the cities of Isin, Larsa, and Eshnunna and extended as far north as Upper Mesopotamia. The dynasty corresponded to a Sumerian renaissance following the fall of the First Dynasty of Ur.