Background:
During the 7th century BCE, the Neo-Assyrian Empire was the dominant power in the region, including Mesopotamia. The Assyrians were known for their brutal military campaigns and oppressive rule over conquered territories. However, a series of events led to the downfall of the Assyrians and the rise of the Neo-Babylonian Empire.

Nabopolassar's Rise to Power:
Nabopolassar, the correct answer to the given question, was a Chaldean prince who rebelled against the Assyrian rule in Babylonia. In 626 BCE, he led an uprising and successfully took control of the city of Babylon, establishing himself as the king. He then formed an alliance with the Medes, another powerful empire in the region, to challenge the Assyrians.

Alliance with the Medes:
Nabopolassar's alliance with the Medes, led by their king Cyaxares, proved to be crucial in the liberation of Babylonia. Together, they launched a joint military campaign against the Assyrians. In 616 BCE, they captured the city of Ashur, the heart of the Assyrian Empire. This victory weakened the Assyrians and marked the beginning of their decline.

Assyrian Defeat and the Fall of Nineveh:
The decisive moment came in 612 BCE when the combined forces of Nabopolassar and Cyaxares laid siege to the Assyrian capital city of Nineveh. After a three-month-long siege, they successfully captured and destroyed the city, effectively ending the Assyrian Empire. This event is considered a significant turning point in ancient history as it marked the end of the Assyrian domination and the rise of new powers.

Nabopolassar's Legacy:
After the fall of Nineveh, Nabopolassar established the Neo-Babylonian Empire, with Babylon as its capital. He is credited with restoring Babylon's cultural and religious institutions and promoting economic prosperity. His reign also saw the construction of several architectural marvels, including the famous Ishtar Gate.

Conclusion:
In 625 BCE, Nabopolassar, the King of Babylon, released Babylonia from Assyrian domination. Through alliances, military campaigns, and the capture of Nineveh, he played a crucial role in the downfall of the Neo-Assyrian Empire and the rise of the Neo-Babylonian Empire.