High Quality Content by WIKIPEDIA articles! High Quality Content by WIKIPEDIA articles! Belshazzar (or Balthazar; Akkadian Bel-sarra-usur) was a prince of Babylon, the son of Nabonidus, the last king of Babylon according to the Book of Daniel. In the Book of Daniel (chapters 5 and 8) of the Jewish Tanakh or Christian Old Testament, Belshazzar is the King of Babylon before the advent of the Medes and Persians.