NOTES for Dan 5:26-28
What stands behind the story of Belshazzar described in Daniel is difficult to say with certainty today. It is known only that the Persians did indeed bring the existence of Babylonia to an end, although at the time of the conquest of Babylonia by the Persian Empire Cyrus, not Darius as the author of the book says, was ruling. In the time when Daniel was written, however, the events of the exile were already perceived as very ancient history, and its details were not so important. Something else was important: the fate of a ruler who challenges God.
At the center of the story is the account of how Belshazzar, the last ruler of Babylonia, decided to use for a feast the sacred vessels once taken from the Jerusalem Temple. This was obvious and unquestionable sacrilege for any Jew, a profanation of a holy thing. And Belshazzar paid for his sacrilege accordingly: he lost not simply power, but the kingdom. Babylonia ceased to exist as a state, and Babylon itself passed under Persian rule.
It is possible that here the author of the book has in mind the events of the Maccabean age connected with the reign of the Syrian king Antiochus Epiphanes, during whose time the book was written. In particular, in the story one can see an allusion to Antiochus' unsuccessful military campaign in Egypt, which, to be sure, did not end in complete collapse but during which Antiochus suffered a serious defeat. It should be noted that the king wanted to vent his anger over the defeat on Judea, which was disobedient to his orders, and this only intensified the anti-Syrian religious war that had already begun there by that moment.
Against such a historical background, the story of Belshazzar's collapse, foretold by Daniel, proved very relevant, for Antiochus Epiphanes also profaned the Jerusalem Temple by ordering pagan altars to be erected in the temple court. The parallels were clear enough. So was the logic of the book's author: he was absolutely convinced that violating the holiness of the Temple was equivalent to an attempt to destroy the house of God, earthly though it was, but sacred; and such attempts are not merely doomed to fail, they destroy the one who undertakes them, destroying him as ruler and as human being.