After the middle of the 12th century BC follows a long period of neglect , but after with the conquest of Babylonia by the Assyrian Sargon II , at the close of the 8th century BC , the city revives . Under Ashurbanipal , about the middle of the 7th century BC , we find Ekur restored with a splendor greater than ever before , the ziggurat of that period being 58 by 39 m. After the middle of the 12th century BC follows another long period of comparative neglect , but with the conquest of Babylonia by the Assyrian king Sargon II , at the close of the 8th century BC , we meet again with building inscriptions , and under Ashurbanipal , about the middle of the 7th century BC , we find Ekur restored with a splendor greater than ever before , the ziggurat of that period being 58 by 39 m. After the fall of the Neo Assyrian Empire Ekur appears to have gradually fallen into decay , until finally , in the Seleucid period , the ancient temple was turned into a fortress .