Complex sentence: Southern Mesopotamia (The Sealand Dynasty) remained independent of Babylonia and in native Akkadian hands until Ulamburiash partly conquered it from "Ea-gamil", a king with a distinctly Sumerian name, around 1450 BC, whereapon Ea-Gamil fled to Elam.
Split into simpler sentences: Southern Mesopotamia (The Sealand Dynasty) remained independent of Babylonia and in native Akkadian hands. However Ulamburiash managed to attack it conquered parts of the land from "Ea-gamil", a king with a distinctly Sumerian name, around 1450 BC, whereupon Ea-Gamil fled to Elam.