But as it was, the Persians were upon them unawares, and by reason of the great size of the city​—so say those who dwell there—​those in the outer parts of it were overcome, yet the dwellers in the middle part knew nothing of it; all this time they were dancing and making merry at a festival . . . till they learnt the truth but too well. [Compare Da 5:1-4, 30; Jer 50:24; 51:31, 32.] Thus was Babylon then for the first time taken.”

The troops under the command of Gobryas and Gadatas caught the guards unawares and gained entrance through the very gates of the palace. In one night “the city was taken and the king slain,” and the Babylonian soldiers occupying the various citadels surrendered the following morning.​—Cyropaedia, VII, v, 33;

that there would be a sudden invasion of the city and a lack of resistance on the part of Babylon’s soldiers. (Isa 44:27; 45:1, 2; Jer 50:35-38; 51:30-32)