How did the chaldeans defeated the assyrian and who helped them?

The Chaldeans, led by King Nabopolassar, defeated the Assyrians with the help of the Medes, an allied power in the region. The two forces combined their military strength to launch a series of coordinated attacks against the Assyrian capital, Nineveh. In 612 BCE, they successfully captured the city, marking the end of Assyrian dominance and the rise of the Neo-Babylonian Empire. This alliance was crucial in overcoming the well-trained Assyrian army, ultimately leading to their downfall.