Photo via The Economist

If you are in London until November 27th, you have a great opportunity to visit “Sunken Cities: Egypt’s Lost Worlds” at the British Museum. The exhibition contains treasures excavated from the Mediterranean and, as the Economist points out, explains how the ancient Greeks knew how to win hearts and minds when it came to subduing Egypt.

In the eighth century AD, earthquakes, floods, and subsidence caused the Egyptian coast at Alexandria, the city founded by Alexander the Great after he took Egypt from the Persians in 332BC, to sink beneath the waves. From the 1960s onwards, teams of underwater archaeologists have been mapping and excavating a whole submerged Graeco-Egyptian world.

Now, for the first time, an exhibition highlights the excavations begun in the 1990s by an underwater team headed by Franck Goddio, founder of the Institut Européen d’Archéologie Sous-Marine (IEASM). Using new technology, Mr. Goddio has located two more sunken cities, Canopus and Thonis-Heracleion, near the western branch of the Nile delta. The cities date back to the seventh century BC, long before the foundation of Alexandria, and their excavation adds to what was already known—that there was extensive commercial and religious interchange between Egypt and the rest of the eastern Mediterranean in the first millennium BC.

Some of this had been learned from work at Naukratis—a harbor city upriver from Canopus and Thonis-Heracleion, which was a trading post to the rest of Egypt. Writing in the fifth century BC, Herodotus (yes, he whose story arc I’ve followed on my own fantasy series, Pearseus) reported that the Egyptian king Amasis had granted Greek traders and sailors special privileges at Naukratis, allowing them to set up sanctuaries to their gods there. Never submerged, Naukratis has been extensively researched from the 1880s onwards.

The show draws as much on Naukratis as on the “sunken cities” of its title, revealing Greeks and Egyptians living side by side, their temples within waving distance, their styles and practices distinct but occasionally overlapping. Archaically smiling alabaster and limestone youths in Egyptian poses, made in Cyprus and found in a Greek sanctuary at Naukratis, give a sense of the sheer cosmopolitanism of the place. And it is there in the smaller things too—a small limestone figure of Horus the child, Greek coins, scarabs and amulets designed for both Greek and Egyptian markets.

Differences, of course, remained. The Greeks always thought the Egyptians strange and exotic. Herodotus said they did everything in reverse and Strabo, a Greek geographer from the first century BC, could never get used to animal worship. For their part, the Egyptians kept foreign trade under tight control. One of the most impressive exhibits, pulled good as new from the sea at Thonis-Heracleion, is an inscribed stone slab, the twin of one found at Naukratis in 1899. Its delicately carved hieroglyphs, here beautifully lit, describe hefty taxes on imports and exports payable to an Egyptian goddess.

This, then, was the background to Alexander the Great and the Ptolemaic dynasty that followed him, who managed as foreigners to rule Egypt for 300 years until 31BC. The existing traffic and mutual accommodation between Greeks and Egyptians smoothed the way, and led to a remarkably canny piece of political diplomacy by the conquerors to go further still—to honor the Egyptian gods outright and to Egyptianise themselves for their subjects. It was a propaganda project, executed with a stylish sense of theater that is mirrored in the whole design and atmosphere of the exhibition itself. Each of these Egyptian gods also corresponded to a Greek deity (there is a helpful chart in the exhibition). And it was precisely by exploiting this fluid system of divine correlations that Alexander and the Ptolemies managed to gain sanction from both sides and legitimize their political power.

Much of this show is about the Osiris cult. There is a magnificent statue of a bull, the Apis, revered in Egypt as an aspect of Osiris and known in its mummified form as Osiris-Apis. The Ptolemies honored this animal deity, but they also had their own Greek version, Serapis, with a human form. A massive sycamore carving of him sits across from the bull, with flowing drapery and loosely curling hair and beard. Such pragmatic and aesthetic shifts between the two cultures are at the heart of the show. Alexandrian workshops could do you Greek-style, Egyptian-style or Graeco-Egyptian-style to order. The Rosetta Stone stipulated that temple statues of Ptolemy V should be “made in the native way”. And a statue of Arsinoe II, a Ptolemy, is a fine example of that fusion: the sculptor, using black Egyptian stone, has posed her “in the native way”, and her garment is tied in the Isis fashion. But her lifelike flesh and the fine lines of her dress proclaim her exquisitely Greek.

The exhibition will be in London until November 27th at the British Museum. You can find out more about it on the Economist.