His cult fell into decline after Nippur was sacked by the Elamites in 1230 BC .
He was eventually supplanted as the chief god of the Mesopotamian pantheon by the Babylonian national god Marduk .
His cult fell into decline after Nippur was sacked by the Elamites in 1230 BC and he was eventually supplanted as the chief god of the Mesopotamian pantheon by the Babylonian national god Marduk .