Fact Check: Did the Chaldeans Capture Nineveh in 612 BCE?

Yes. The Chaldean (Neo-Babylonian) king Nabopolassar, allied with the Median king Cyaxares, besieged Nineveh for three months in the summer of 612 BCE. The city fell, was sacked, and burned. The Assyrian king Sinsharishkun likely died in the conflagration. This event ended the Neo-Assyrian Empire as a political entity.

The Coalition

• Babylonians (Chaldeans): Nabopolassar, a former Assyrian general turned rebel, had consolidated Babylonia by 616 BCE.
• Medes: Cyaxares unified Iranian tribes; his cavalry was decisive in open field.
• Others: Scythians, Cimmerians, and disaffected Assyrian vassals joined.

The Siege

Nineveh's walls were massive (12 km circuit, 15 gates), but the Khosr River was diverted to flood the defenses. Assyrian relief armies failed to materialize—civil war and Egyptian non-intervention left the capital isolated. The Babylonian Chronicle (BM 21901) records: "In the month Abu... the king of Akkad and his army... encamped against Nineveh... they carried off the vast booty of the city... and turned the city into a ruin heap."

Aftermath

Assyrian remnants fled to Harran under Ashur-uballit II, backed by Egypt. They held until 609 BCE, when Babylonian-Median forces took Harran. The Assyrian state ceased to exist. Babylon inherited the Fertile Crescent; Media took the east. The Chaldean dynasty (Nabopolassar → Nebuchadnezzar II → ...) ruled Babylon until Cyrus the Great's Persian conquest in 539 BCE.

So yes—612 BCE, Chaldeans (and Medes), Nineveh fell. History's receipts are in the British Museum.