Babylon wasn't the capital of the Neo-Babylonian Empire.
The early Persian kings had attempted to maintain the religious ceremonies of Marduk, who was the most important god, but by the reign of Darius III, over-taxation and the strain of numerous wars led to a deterioration of Babylon's main shrines and canals, and the destabilization of the surrounding region
However, Babylon maintained its own culture and people, who spoke varieties of Aramaic, and who continued to refer to their homeland as Babylon

