Simplify the following text for a Grade 12 native English-speaking person.
Original: The city lost its prime importance around 2000 BC , in the context of the struggle of Babylonia with Elam , but it remained inhabited throughout the Seleucid and Parthian periods until it was finally abandoned during the Sassanid period shortly before the Islamic conquest of Mesopotamia .
Simplified: The city lost its prime importance around 2000 BC , after the struggle of Babylonia with Elam . It remained inhabited throughout the Seleucid and Parthian periods until it was finally abandoned during the Sassanid period , just before the Islamic conquest of Mesopotamia .