Then he had other towers built along the mound, so as to have as many guard-posts as possible.

[13] Thus his army was employed, but the men within the walls laughed at his preparations, knowing they had supplies to last them more than twenty years.

When Cyrus heard that, he divided his army into twelve, each division to keep guard for one month in the year.

[14] At this the Babylonians laughed louder still, greatly pleased at the idea of being guarded by Phrygians and Lydians and Arabians and Cappadocians, all of whom, they thought, would be more friendly to themselves than to the Persians.
[15] However by this time the trenches were dug.

And Cyrus heard that it was a time of high festival in Babylon when the citizens drink and make merry the whole night long.