officially used for administration, although the Sumerian language remained as a spoken and literary language. The spread of Akkadian stretched from Syria to Elam, and even the Elamite language was temporarily written in Mesopotamian cuneiform. Akkadian texts later found their way to far-off places, from Egypt (in the Amarna Period) and Anatolia, to Persia (Behistun). Submission of Sumerian kings The submission of some Sumerian rulers to the Akkadian Empire, is recorded in the seal inscriptions of Sumerian rulers such as Lugal-ushumgal, governor (ensi) of Lagash ("Shirpula"), circa 2230-2210 BC. Several inscriptions of Lugal-ushumgal are known, particularly seal impressions, which refer to him as governor of Lagash and at the time a vassal (, arad, "servant" or "slave") of Naram-Sin, as well as his successor Shar-kali-sharri. One of these seals proclaims: It can be considered that Lugal-ushumgal was a collaborator of the Akkadian Empire, as was Meskigal, ruler of Adab. Later however, Lugal-ushumgal was succeeded by Puzer-Mama who, as Akkadian power waned, achieved independence from Shar-Kali-Sharri, assuming the title of "King of Lagash" and starting the illustrious Second Dynasty of Lagash. Collapse The empire of Akkad likely fell in the 22nd century BC, within 180 years of its founding, ushering in a "Dark Age" with no prominent imperial authority until the Third Dynasty of Ur. The region's political structure may have reverted to the status quo ante of local governance by city-states. By the end of Sharkalisharri's reign, the empire had begun to unravel. After several years (and 4 kings) of chaos Shu-turul and Dudu appear to have restored some centralized authority for several decades however they were unable to prevent the empire eventually collapsing outright, eventually ceding power to Gutians, based in Adab, who had been conquered by Akkad in the reign of Sharkalisharri. Little is known about the Gutian period, or how long it endured. Cuneiform sources suggest that the Gutians' administration showed little concern for maintaining agriculture, written records, or public safety; they reputedly released all farm animals to roam about Mesopotamia freely and soon brought about famine and rocketing grain prices. The Sumerian king Ur-Nammu (2112–2095 BC) cleared the Gutians from Mesopotamia during his reign. The Sumerian King List, describing the Akkadian Empire after the death of Shar-kali-shari, states: However, there are no known year-names or other archaeological evidence verifying any of these later kings of Akkad or Uruk, apart from several artefact referencing king Dudu of