Who was the last king of Babylon?
Belshazzar
Belshazzar (/bɛlˈʃæzər/; Hebrew: בֵּלְשַׁאצַּר, Belshatsar, Greek: Βαλτάζαρ, Baltázar, from Akkadian: 𒂗𒈗𒋀, Bēl-šar-uṣur, meaning "Bel protect the king")[3] was the eldest son of Nabonidus, the last king of the Neo-Babylonian empire, and regent for his father during the latter's prolonged absence from the city, although he never assumed the titles or ritual functions of kingship.[4] He may have been killed when Babylon fell to the Persians in 539 BCE.[5]
Eastern Arabia
One of the early sites discovered in Bahrain indicate that Sennacherib, king of Assyria (707–681 BC), attacked northeast Persian Gulf and captured Bahrain. The most recent reference to Dilmun came during the Neo-Babylonian dynasty. Neo-Babylonian administrative records, dated 567 BC, stated that Dilmun was controlled by the king of Babylon. The name of Dilmun fell from use after the collapse of Neo-Babylon in 538 BC.