What is "ishbi-erra"

Išbi-erra was the founder of the 1st Dynasty of Isin, the successors to the neo- Sumerian Ur III kingdom in ancient southern Mesopotamia. According to the Weld-Blundell Prism, he reigned for 33 years and this is corroborated by the number of his extant year-names, 1953 BC - 1921 BC ( short chronology). His name was written phonetically in cuneiform: iš-bi-èr-ra, in contemporary inscriptions. While in many ways this dynasty emulated that of the preceding one, its language was Akkadian as the Sumerian language had become moribund in the latter stages of the Third Dynasty of Ur.