In the autumn of the year 539 Cyrus entered the city in triumph, and was received with such manifestations of joy by the populace, as to make one almost forget that with his entrance, the end of a great empire had come.

Politically and religiously, the history of Babylonia and Assyria terminates with the advent of Cyrus; and this despite the fact that it was his policy to leave the state of affairs, including religious observances, as far as possible, undisturbed.

A new spirit had, however, come into the land with him.

The official religion of the state was that practiced by Cyrus and his predecessors in their native land.

The essential doctrines of the religion, commonly known as Mazdeism or Zoroastrianism, presented a sharp contrast to the beliefs that still were current in Babylonia, and it was inevitable that with the influx of new ideas, the further development of Babylonian worship was cut short.
The respect paid by Cyrus to the Babylonian gods was a mere matter of policy.