According to the Nabonidus Chronicle, Cyrus, in the month Tashritu (Tishri [September-October]), attacked the Babylonian forces at Opis. The inscription continues: “The 14th day, Sippar was seized without battle. Nabonidus fled. The 16th day, Gobryas (Ugbaru), the governor of Gutium and the army of Cyrus entered Babylon without battle. Afterwards Nabonidus was arrested in Babylon when he returned.”​—Ancient Near Eastern Texts, edited by James B. Pritchard, p. 306.

Though the year is not found in the Nabonidus Chronicle itself, the available evidence is nevertheless sufficient for accepting 539 B.C.E. as the date for Babylon’s fall. Of course, this factor does lessen the value of the Nabonidus Chronicle in determining the time for the event. But the inscription is still of considerable value, for it provides noteworthy testimony concerning the manner of Babylon’s fall. Also, since the inscription shows that Nabonidus was not in Babylon at the time of the city’s fall, this explains why the Bible does not mention him by name. However, the Holy Scriptures imply his existence in that Belshazzar is shown to have offered Daniel the third position in the kingdom, the first being held by Nabonidus and the second by Belshazzar.​—Dan. 5:16.