The exact events surrounding Isin's rapid disintegration…

The exact events surrounding Isin's rapid disintegration as a kingdom are largely unknown, but some evidence can be pieced together.

Isin's rulers may have allowed the once-burgeoning irrigation and agricultural systems to wane, but documents indicate that access to water sources had presented a huge problem for Isin.

The city-state also endures an internal coup of a sort when a royally appointed Amorite governor of the Lagash province, Gungunum, for reasons undetermined breaks with Isin and establishes an independent dynasty in Larsa, which has long been more under Elamite than Sumerian influence.

To legitimize his rule and deliver a blow to Isin, an Amorite center, Gungunum seizes the town of Ur, which is not only a significant religious center but is the main portal to the profitable Gulf trade; this move economically cripples Isin.