[5] According to the Nippur vase of Lugalzagesi,[6][7] Lugal-Zage-Si was the son of Ukush, governor of Umma: "Lugal-zagesi-si, King of Uruk, King of the Land, priest of Ana, prophet of Nidaba; the son of Ukush, patesi of Umma, the prophet of Nidaba; he who was favourably regarded by Ana, the king of the lands; the great patesi of Enlil; endowed with understanding by Enki; whose name was spoken by Babbar (the Sun-god), the chief minister of Enzu (the Moon-god), the representative of Babbar, the patron of Ninni, the son of Nidaba, who was nourished with holy milk by Ninkharsag, the servant of the god Mes, who is the priest of Uruk, the pupil of Ninabukkhadu, the mistress of Uruk, the Great Minister of the gods".Lugal-Zage-Si pursued an expansionist foreign policy.

In the seventh year of his reign, Uruk fell under the leadership of Lugal-Zage-Si, énsi of Umma, who ultimately annexed most of the territory of Lagash under king Urukagina, and established the first reliably documented kingdom to encompass all of Sumer.

The destruction of Lagash was described in a lament (possibly the earliest recorded example of what would become a prolific Sumerian literary genre), which stressed that: "The man of Umma ... committed a sin against Ningirsu.

"Although his incursion to the Mediterranean was, in the eyes of some modern scholars, not much more than "a successful raiding party", the inscription "marks the first time that a Sumerian prince claimed to have reached what was, for them, the western edge of the world".

[14] (Historical accounts from much later tablets asserted that Lugal-Anne-Mundu of Adab, a slightly earlier king, had also conquered as far as the Mediterranean and the Taurus mountains, but contemporary records for the entire period before Sargon are still far too sketchy to permit scholars to reconstruct actual events with great confidence.)

May the land in riverine meadows rest (contentedly) under me, may the people like sweet-smelling grasses spread out widely under me, may the breast of heaven function properly under me, and may the nation behold a pleasant place under me.