‘Belshazzar the king made a great feast to a thousand of his lords, and drank wine before the thousand.'
The abrupt introduction of the subject is typical of the author (compare Daniel 3:1; Daniel 4:1). Belshazzar (mentioned as Bel - shar - usur on cuneiform tablets, where he is always called ‘son of the king') was the grandson of Nebuchadnezzar, and son of Nabonidus, the latter later in life going into semi-retirement in Arabia to study astrology, leaving Belshazzar to act in his place as king. A Persian document says of Nabonidus ‘he freed his hand. He entrusted the kingship to him. Then he himself undertook a distant campaign', demonstrating that it was not the first time he had done it. Decrees were issued in their joint names, and their names were regularly associated in various ways. Thus while not strictly ‘sharru' (overall king) Daniel is justified in calling him ‘melek', ruler, as he also does Cyrus' general, Darius the Mede, for he exercised kingly authority and was more than just a governor.
The ‘thousand' is a round number meaning ‘a good number'. The word ‘a thousand' was used among other things to depict a larger military unit, as against ‘a hundred' or ‘a ten'. Large feasts like this were typical of oriental royal feasts. Indeed there were much larger ones. That a great feast was held on the night of the fall of Babylon is attested by both Herodotus and Xenophon. During the feast Belshazzar became inebriated. The drinking of wine was a large part of such feasts.
This gathering took place while the city of Babylon was surrounded by enemies, for the Medo-Persians had invaded Babylonia under one of Cyrus' generals named Ugbaru, and the city was virtually under siege. But due to their strong defences they were confident of holding out.
‘Drank wine before the thousand.' The king would be seated alone at his table on a raised platform as befitted his status.