Chapter 5 takes place an estimated 9 years after Nebuchadnezzar’s death and about 36 years after the previous chapter. Belshazzar was Nebuchadnezzar’s grandson who took control of the kingdom as his father was on extended leave fighting the Persians. It appears that Daniel had retired from his high place in government. He would have been pretty old at this point, though he also could have lost his position when Nebuchadnezzar died.
The walls of Babylon were 87 feet thick and 100 feet high
It was fairly common for the kings to dine with such large numbers of people as you can see in Esther 1. In this case though, the invading armies are right outside the city walls. This would seem to be incredible arrogance similar to his grandfather, but Herodotus tells us that Babylon had two walls surrounding the city with a moat in between. The walls were 87 feet thick and 100 feet high, so conquering Babylon was not something that happened easily. At the end of the chapter we find out that this would be the night it was captured. Herodotus corroborates the Bible and mentions a festival was going on the night the city was conquered.
Regardless of the city’s security, it was a bad decision to get drunk in front of your lords with an invading army outside. Even worse to taunt a god by desecrating sacred items collected from a temple. Maybe he was doing this to instill a sense of pride to his lords reminding them of past victories, though Daniel seems be very specific about his lack of sobriety.
The handwriting on the wall has always stood out to me as a bizarre miracle by God (bizarre by miracle standards that is). This seems like something you would see in a horror movie. The best interpretation I found of the Aramaic writing said it literally translated to “numbered, numbered, weighed, divided.”
Belshazzar was not given a message of repentance but rather a proclamation of impending judgement. It is evident to us that although the king is just informed of his doom, God had been moving the Medes and Persians in place to execute his plan for some time.
Extra-biblical writings tell us that the Persians blocked the flow of the Euphrates and walked on the riverbed to an unguarded portion of the wall where they climbed up without opposition. Since so many were gathered at the festival, the Babylonians were defeated with relative ease.
Numbered, numbered, weighed, divided
Darius the Mede is not found anywhere else in extra-biblical writings and is a serious point of contention for Bible critics. Cyrus was definitely the king of Persia, so Darius could either be a Babylonian nickname or title similar to Caesar or Pharoah. It also could be referring to the local ruler that Cyrus put in charge of that area. There is no evidence to identify Darius the Mede, but there is also no hard evidence contradicting it.