The empire ruled from Babylon between roughly 626 and 539 BCE, often called the Chaldean Empire after the dynasty that founded it. Nabopolassar broke free of Assyrian rule and, allied with the Medes, helped destroy Nineveh in 612 BCE; his son Nebuchadnezzar II (r. 605–562 BCE) made Babylon the monumental capital of the Near East, rebuilding it with the Ishtar Gate and a great ziggurat. The empire sacked Jerusalem in 587/586 BCE and deported much of its population, the event known as the Babylonian Captivity. It fell to Cyrus the Great's Persians in 539 BCE under its last king, Nabonidus.
For centuries the great library of Babylon's scholars was filled with diaries of the night sky. Night after night, trained observers climbed the temple towers and wrote down where the moon and planets stood, when eclipses came, how high the river ran, and what grain cost in the market. They were not idle stargazers. They believed the heavens spoke, and that a king who read the signs could see disaster coming. From this patient watching grew records so long and exact that astronomers a thousand years later still used them. They were the work of a Babylonian scholarly tradition far older than any single dynasty. The empire at the heart of this story ruled the Near East for less than a century, yet it left two things the world never forgot: the most famous city of the ancient world, and a captivity that reshaped a religion.