With Assyria gone, Babylon rose for one last time as the center of an empire. Nabopolassar, a Chaldean leader who had helped destroy Nineveh, founded what historians call the Neo-Babylonian empire. His son Nebuchadnezzar II, who ruled from 605 to 562 BCE, won the Levant from Egypt and poured its wealth into rebuilding his capital. The Babylon he left was among the largest and most splendid cities on earth.

Nebuchadnezzar's Babylon

Babylon under Nebuchadnezzar had double walls, a moat, a bridge over the Euphrates and a great ziggurat called Etemenanki, "house that is the foundation of heaven and earth," which many scholars connect with the biblical Tower of Babel. Visitors entered the inner city along a processional way through the Ishtar Gate. The Ishtar Gate was decorated with blue glazed bricks showing dragons and bulls, the animals of the gods Marduk and Adad, while lions lined the walls of the processional way.

Nebuchadnezzar also put down a revolt in the kingdom of Judah. His army captured Jerusalem in 597 BCE and, after a second revolt, Jerusalem was destroyed under Nebuchadnezzar II and many of its people deported to Babylonia in 587 or 586 BCE.

The most famous wonder of Babylon may never have stood there. Greek writers described Hanging Gardens built on terraces. Historians are puzzled because no Babylonian text ever mentions the Hanging Gardens, despite many detailed building inscriptions from Nebuchadnezzar. The Assyriologist Stephanie Dalley has argued that the gardens were really Sennacherib's at Nineveh and were later confused with Babylon. Others think they existed but were too minor for the king to record. The question remains open.

The last king of Babylon

The final Babylonian king, Nabonidus, who ruled from 556 to 539 BCE, was an unusual man. He spent about ten years at the oasis of Tayma in Arabia, leaving his son Belshazzar in charge, and he dug into old temple foundations to find inscriptions of earlier kings, which has earned him the nickname of the first archaeologist. Nabonidus angered Babylon's priests because he favored the moon god Sin over Marduk, the city's own god. In 539 BCE the Persian king Cyrus the Great defeated the Babylonian army and entered Babylon, reportedly without a fight.

The Cyrus Cylinder

A clay cylinder found in Babylon in 1879 by Hormuzd Rassam, now in the British Museum, tells the Persian side. The Cyrus Cylinder describes how Cyrus took Babylon and restored its gods: Marduk, angry at Nabonidus, chose Cyrus to rule, and Cyrus returned divine statues and displaced peoples to their homes. In the twentieth century the cylinder was hailed as the first charter of human rights, and a replica is displayed at the United Nations in New York. Most historians doubt the cylinder is a human rights charter because it follows the pattern of older royal inscriptions: a new king blames his predecessor, claims divine choice and lists his good works. It contains no general statement of rights. Yet it does record a real policy of tolerance toward local gods and of letting deported peoples go home, which fits the biblical memory of Cyrus allowing the exiles of Judah to return.

The long fade and the legacy

Mesopotamia remained rich and important under Persian rule. Cuneiform slowly gave way to Aramaic and Greek, kept alive mainly by temple scholars and astronomers. The latest datable cuneiform tablet, an astronomical almanac, comes from around 79 to 80 CE.

The legacy is everywhere. Dividing hours into sixty minutes comes from Mesopotamian base-sixty counting, as does the circle of 360 degrees. Babylonian astronomers created the zodiac of twelve equal signs, and their records fed Greek astronomy. From the 1840s European excavators such as Paul-Emile Botta and Austen Henry Layard dug up Assyrian palaces and shipped their finds to Paris and London, and later generations of Iraqi archaeologists took over the work in their own country.

That heritage remains fragile. In April 2003, the Iraq Museum in Baghdad was looted of thousands of objects, about 15,000 by most estimates, of which a large share has since been recovered. In 2015 the militants of the Islamic State filmed themselves smashing sculptures and blowing up the palace at Nimrud. Protecting these remains is not only about old stones. It is about the right of Iraqis, and of everyone, to know the story of the first cities.

Worked example: A king on the ration list

During the German excavations at Babylon, workers found tablets in a vaulted building near the Ishtar Gate. Published in 1939, they turned out to be ration lists from Nebuchadnezzar's reign, recording oil and barley handed out to foreigners living at the court: craftsmen and sailors from Egypt, Phoenicia, Elam, Persia and Greece. Among them is Jehoiachin, king of Judah, with his five sons. Second Kings, written for a very different purpose, says that Jehoiachin was taken to Babylon and later given a regular allowance at the king's table.

The match is striking, but notice its limits. The tablets confirm that a captive king of Judah lived at Babylon and drew rations. They do not confirm every detail of the biblical story, and they were never meant to. They also show what Nebuchadnezzar's capital was: a city full of displaced people from across the Near East, fed by the state that had uprooted them.