If you had chanced to visit the site of ancient Babylon during the past century, your guide would have proudly shown you the site of the Hanging Gardens, one of the seven wonders of the ancient world. You would have gazed, perplexed, at the eroded walls of a palace built by Nebuchadnezzar in the 6th-century BC. Its German excavator, Robert Koldewey, had searched methodically yet desperately for the famous garden and had suggested that it might be a roof garden within the palace because bitumen and baked brick would have helped to waterproof the structure. He found no supporting evidence in Nebuchadnezzar’s inscriptions. He could not match any feature of such a garden in the accounts of Greeks who wrote many centuries later. Above all, nothing he found could have qualified as a world wonder on a par with the Lighthouse at Alexandria or the Great Pyramid or the Colossus of Rhodes.
So unsatisfactory was this solution, that some scholars suggested the Hanging Gardens were legendary in the sense that they were a pure fiction attached spuriously to a famous king and a famous city. Few of them noticed that the only later writer to name the builder as Nebuchadnezzar was Josephus, ostensibly quoting from Berossus who was a Babylonian priest. But Josephus has a reputation for embellishing his narrative to please his readers in Jerusalem. Another source named the king as an Assyrian who ruled in Babylon. And there was a story in circulation that the legendary Semiramis was the builder.
Long before Robert Koldewey excavated at Babylon, an Englishman, Austen Henry Layard, dug at Nineveh, guided by the Old Testament and by Xenophon’s March of the Ten Thousand. He tunnelled into the palace of the 8th- to 7th-century Assyrian king Sennacherib and unearthed great stone panels of bas-relief sculpture for the British Museum. One of them, quite damaged, depicted a garden with some of the features of the Hanging Gardens as described by those later Greek writers. Around the same time another, much more badly damaged, panel was found showing some of the same features but including a pillared walkway roofed with trees. An “Original Drawing” of it is in the British Museum; the panel did not survive. The pillared walkway, roofed with layers of soil planted with trees, is a specific item in the description of two of the Greek authors. Layard published the drawing in 1853.
Several decades after Layard’s discoveries, a hexagonal clay prism inscribed by Sennacherib came to light. An edition of the text written on it was published in Chicago in 1924, at a time when the understanding of Assyrian inscriptions was still in progress. The text contained a technical passage concerning casting in bronze and the installation of a new machine for raising water, but the translation given made poor sense. It was not connected with the Hanging Garden until 1994, when I showed that the technical terms had been misunderstood, and referred to a spiral and a cylinder, cast in bronze: two elements of an Archimedean screw. Both Strabo and the much later Paradoxographer Philo of Byzantium wrote that the Hanging Gardens were watered with a screw, even though Strabo would have been well aware that Archimedes lived several centuries later than Sennacherib or Nebuchadnezzar.
The main panel of sculpture found by Layard showed an aqueduct bringing water into the garden half way up its terraces, a layout that also matched Greek accounts. The garden, they said, resembled a Greek theatre. The panel joined or near-joined another panel showing the palace.
These were clues sufficient to solve the mystery, but it remained to show how Nineveh on the Tigris in northern Iraq became confused with Babylon on the Euphrates in central Iraq. It remained to show what an astonishing feat of Assyrian engineering brought water to the high citadel, over a distance of 50 miles, at just the right height to keep the garden irrigated.
An essential difference in the topography of Nineveh and Babylon shows that the Hanging Gardens, as described in Greek texts, could not have existed in Babylon. Flat terrain stretches on both sides of the Euphrates at Babylon, so no tributaries exist to bring water from elevated ground. Therefore the oasis-type gardens in that region are flat, irrigated by canals, and planted with date-palms, figs and pomegranates. In the north at Nineveh, on the other hand, mountains and tributaries to the east allow water to flow down, controlled by aqueducts and weirs, to the high citadel. The tradition of gardens there imitates mountainous scenery, with aromatic trees, lakes and fast-flowing streams. This northern, Assyrian style of garden is shown on a panel of sculpture found in the palace of Sennacherib’s father, Sargon, now in the Oriental Institute in Chicago.
Taking all the evidence into account, the late Terry Ball, a chief illustrator for English Heritage, contributed a splendid reconstruction drawing of the garden beside the palace.
The creation of Sennacherib’s wonder-garden at Nineveh is far removed in time from the Greek descriptions. Herodotus never mentioned it. So why do we find such a late literary tradition?
When Alexander the Great crossed the upper Tigris, outmanoeuvring Persian generals, and encamped to the east of Nineveh before the Battle of Gaugamela, he was positioned close to the great stone aqueduct at Jerwan, where Sennacherib’s inscriptions are still as clear as the day they were chiselled. From the mountain peak of the Jebel Maqlub he could look westwards towards Nineveh and eastward over the astonishing network of canals, aqueducts and magnificent royal rock sculptures showing the king like a god in the company of the great gods of Assyria and Babylonia. Alexander spent many days there before the great battle that took its name from the river Gomel and its town Tell Gomel. His historians, astonished at the sights, wrote their tales of the exotic orient based on their experiences, but because their accounts have not survived we have to rely on the use made of them by later writers. That is why Herodotus, who described Babylon but not Nineveh, does not mention the Hanging Gardens. And it explains why there is such a huge gap between Sennacherib’s creation of the garden with its spectacular watering arrangements and the Greek authors on whose descriptions we can now rely because they match so well with the sculptures and inscriptions found at Nineveh. It is possible that the garden was still visible in Alexander’s time, for Layard and his successors found evidence for continuity despite the hyperbole of Xenophon and Nahum.
At last we can see why the Hanging Gardens ranked among the seven world wonders, as an extraordinary technical achievement making possible a spectacular sight.
‘The Mystery of the Hanging Garden of Babylon: An Elusive World Wonder Traced’ by Stephanie Dalley, Oxford University Press, £25