Labashi-Marduk in the context of "Fall of Babylon"

The Chaldean dynasty, also known as the Neo-Babylonian dynasty and enumerated as Dynasty X of Babylon, was the ruling dynasty of the Neo-Babylonian Empire, ruling as kings of Babylon from the ascent of Nabopolassar in 626 BC to the fall of Babylon in 539 BC. The dynasty, as connected to Nabopolassar through descent, was deposed in 560 BC by the Aramean official Neriglissar (r. 560–556 BC), though he was connected to the Chaldean kings through marriage and his son and successor, Labashi-Marduk (r. 556 BC), might have reintroduced the bloodline to the throne. The final Neo-Babylonian king, Nabonidus (r. 556–539 BC), was genealogically unconnected to the previous kings, but might, like Neriglissar, also have been connected to the dynasty through marriage.

Belshazzar (Babylonian cuneiform:   Bēl-šar-uṣur, meaning "Bel, protect the king"; Hebrew: בֵּלְשַׁאצַּר‎ Bēlšaʾṣṣar) was the son and crown prince of Nabonidus (r. 556 – 539 BC), the last king of the Neo-Babylonian Empire. Through his mother, he might have been a grandson of Nebuchadnezzar II (r. 605 – 562 BC), though this is not certain and the claims to kinship with Nebuchadnezzar may have originated from royal propaganda.

Belshazzar played a pivotal role in the coup d'état that overthrew the king Labashi-Marduk (r. 556 BC– ) and brought Nabonidus to power in 556 BC. Since Belshazzar was the main beneficiary of the coup, through confiscating and inheriting Labashi-Marduk's estates and wealth, it is likely that he was the chief orchestrator. Through proclaiming his father as the new king, Belshazzar also made himself the first-in-line to the throne. As Nabonidus was relatively old at the time, Belshazzar could expect to become king within a few years.