Here's a breakdown:
* Cyrus the Great rose to power in Persia and began a campaign of conquest that eventually brought him to the doorstep of Babylon.
* In 539 BCE, Cyrus' forces successfully captured the city of Babylon. The city, which was heavily fortified and had a strong army, was taken through a combination of strategic planning, diplomatic maneuvering, and possibly even a betrayal by a Babylonian official.
* The conquest of Babylon marked a significant shift in the balance of power in the ancient world, marking the end of the Neo-Babylonian Empire and the rise of the Persian Empire as a dominant force.
While the Neo-Babylonian Empire had experienced periods of decline after Nebuchadnezzar II's death, the final blow was delivered by Cyrus the Great and his Persian armies. This victory helped establish Cyrus as a great king and led to the formation of the vast Achaemenid Persian Empire.