Learn more about Belshazzar from the Easton’s Bible Dictionary

Bel protect the king!, the last of the kings of Babylon (Dan. 5:1). He was the son of Nabonidus by Nitocris, who was the daughter of Nebuchadnezzar and the widow of Nergal-sharezer. When still young he made a great feast to a thousand of his lords, and when heated with wine sent for the sacred vessels his "father" (Dan. 5:2), or grandfather, Nebuchadnezzar had carried away from the temple in Jerusalem, and he and his princes drank out of them. In the midst of their mad revelry a hand was seen by the king tracing on the wall the announcement of God's judgment, which that night fell upon him. At the instance of the queen (i.e., his mother) Daniel was brought in, and he interpreted the writing. That night the kingdom of the Chaldeans came to an end, and the king was slain (Dan. 5:30). (See [58]NERGAL-SHAREZER.)
The absence of the name of Belshazzar on the monuments was long regarded as an argument against the genuineness of the Book of Daniel. In 1854 Sir Henry Rawlinson found an inscription of Nabonidus which referred to his eldest son. Quite recently, however, the side of a ravine undermined by heavy rains fell at Hillah, a suburb of Babylon. A number of huge, coarse earthenware vases were laid bare. These were filled with tablets, the receipts and contracts of a firm of Babylonian bankers, which showed that Belshazzar had a household, with secretaries and stewards. One was dated in the third year of the king Marduk-sar-uzur. As Marduk-sar-uzar was another name for Baal, this Marduk-sar-uzur was found to be the Belshazzar of Scripture. In one of these contract tablets, dated in the July after the defeat of the army of Nabonidus, we find him paying tithes for his sister to the temple of the sun-god at Sippara.