Jeremiah 51:31

We have had occasion one and again to recite what we have in civil historians about the taking of Babylon by Cyrus, viz., that it was taken by surprise, by the Median emperor's unexpected diverting the river Euphrates by divers channels which he cut; as also that Babylon was a very vast city, the greatness of which might admit of posts and messengers from one end of the city to another, to acquaint the king what was done at the other end of the city in which himself was resident; and it is said that the king of Babylon, when his city, was taken, did not know of his danger until the enemy had entered the city.