Belshazzar (/bɛlˈʃæzər/; Biblical Hebrew בלשאצר; Akkadian: Bēl-šarra-uṣur; Greek: Balthazar, from Akkadian, meaning "Protect His Life"; or, possibly, "[May] Bel Protect the King";) was Coregent of Babylon, governing the country after his father, King Nabonidus, went into exile in 550 BCE.