I just found another instance of Belshazzar being referred to as the "son of Nebuchadnezzar". It's truly remarkable!
The source, I never would have thought of examining: the Book of Baruch, included in the Septuagint and Vulgate - and it is attributed, if taken literally as well, to Jeremiah's scribe. Final chapter 6 is a letter dictated by the prophet; the 1st is introductory commentary where we get clarification of whether "son of Nebuchadnezzar" for Belshazzar was meant in general sense of descendant. Move over, King Nabonidus.
In chapter 6, in the text of the letter, it begins:
"Because of the sins which you have committed before God, you are to be deported by Nebuchadnezzar king of the Babylonians. Once you have reached Babylon you will stay there for many years, as long as 7 generations, after which I shall bring you home in peace. [ 7 generations? What about 70 years?]
Now in Babylon, you will see gods made of silver, of gold, of wood, being carried shoulder high..."
So far so good? Heard that expression a few times.
Now in the first chapter this material is introduced as follows:
This is the text of the book written in Babylon by Baruch son of Neraiah, son of Mahseaih, .... in the 5th year on the on the 7th day of the month, at the time when the Chaldeans had captured Jerusalem and burned it down.
1:3 Baruch read text of this book aloud to Jeconiah son of Jehoiakim, king of Judah, and to all the people who had come to hear...
1:11 Now pray for the long life of Nebuchadnezzar king of Babylon and of his son Belshazzar, that they may endure on earth as long as the heavens endure;...
1:12and that we may lead our lives under the protection of the king of Babylon and of his son Belshazzar, and that we may serve them for a long time and win their favor."
Well, it is hard to make a case one way or another from this translation about whether it's the same author as chapter 5 of Daniel, but certain elements are in common.
Yet there is one big clarification. The author does not know of the existence of Nabonidus. He thinks that Belshazzar as a regent was living circa 582 BC.
In the prayer of Nabonidus which has similarities to the story of Nebuchadnezzar's madness, the first person narrative seems to lack Nabonidus's name, but it speaks of exile to the Arabian city of Teima. Hence, the modern reader with Babylonian tablets available infers this is Nabonidus recorded elsewhere as having spent considerable time thereabouts. This was an artifact of Qumrum or the Dead Sea.
The problem with all of these stories is that the card deck of much Biblical study is shuffled to make the best match with prevailing orthodoxies - and to emphasize the prophetic nature of Daniel. The defense of chapter 5's genealogy was that the author was referring to Belshazzar as a descendant of Nebuchadnezzar in the same sense as all Jews were sons of Abraham. Just the way people talk in the Mesopotamian valley - You know.
But whoever wrote Baruch begs to differ. Possible reasons:
1. Daniel was written by the same author or authors closely related. So to speak, Baruch does not mention Daniel, but they collaborated or shared the same library sources, whatever date they wrote their books.
2. Baruch's author was not present at the time but interpreted chapter 5 of Daniel accordingly. That creates problems for Baruch's veracity and date of origination. But very likely Baruch was written at a late date. It too has remnants at Qumrum though. And as part of the Septuagint and Vulgate, it says something about incorporation process.
Is it not odd that the text of Baruch is not marshalled to the defense of Daniel's assertions?
Nowadays, Protestant and NWT bibles do not include such deuteron-canonical books in their texts. But there is not a clear explanation as to why. One could suppose that these decisions are based on deliberations where the shortcomings of these works (authenticity or antiquity) were somehow exposed though the cases of Maccabees, for example, and Baruch would be considerably different in nature). Same with adding chapters 13 and 14 to Daniel. But Maccabees puts the prophecies of Daniel in an historical context within the framework of the Bible - and Baruch does much the same to its genealogical claims, besides throwing a window open on the spirituality of the Hellenic period.
Better to leave well enough alone with 2520 years to 1914, etc.