Readers of Cornucopia will be delighted with Philip Mansel’s long-awaited return to the shores of the eastern Mediterranean, whose imperial capital he explored so brilliantly in Constantinople: City of the World’s Desire. His latest book, Levant: Splendour and Catastrophe, focuses on three less imperial cities, with a sideways glance at Thessalonika: cities on the edge of the Ottoman Empire in which a hybrid society arose to channel trade.

Izmir, Beirut and Alexandria were always going to be important ports: Izmir, or Smyrna, was the entrepôt of Asia Minor in the days of Herodotus, who was born there; Alexandria was a colossus of the classical world; Beirut’s own history is Phoenician. What gave them – and Constantinople, too – a twist was Ottoman rule, and a foreign policy which opened up these cities to foreign trade and settlement.

Religious tolerance in the Ottoman Empire stands in attractive contrast to the intransigence of contemporary Christian Europe, though in effect the Ottomans had little choice but to regulate the affairs of non-Muslim minorities through their religious leaders, the so-called millet system. After the Ottoman conquest of Istanbul, the Venetians in the empire were placed under a bailo, who continued a practice established in Byzantine times of representing, protecting and regulating his countrymen. In 1569 a more extensive version of the Venetian arrangement, with 18 articles, or capitulae, was granted to the French. The new agreement gave them freedom of commerce, of dress and worship; it exempted them from Ottoman tax and forced labour, and subjected them to their own laws, exercised through the consul, in all matters except murder. Similar “capitulations” were later made with the English and the Dutch, and they established the framework of the Levantine world for the next three centuries.

As all the Dutch impedimenta of modern trade – interest, loans and the like – came onstream, the wisdom of exempting the merchants from sharia law became obvious. The fortune-hunters arrived and prospered. The foreign consuls – French, Dutch and English – in Smyrna lived like princes, their merchants like lords. Trade boomed. Jews moved in from the Mediterranean diaspora; the Greeks poured in, especially after the War of Independence. By the 19th century Izmir’s population of half a million was roughly divided between Muslim Turks and the Orthodox, Jewish and Western Europeans. The churches rose beside the mosques, a dozen languages were spoken on the street, and a gilded café society propped up by the usual 19th-century panoply of newspapers flourished along the Cordon, which flanked the sea.

Something similar occurred in Alexandria, after Mehmed Ali took control. He and his heirs presided over an explosion of foreign trade. This city, too, was predominantly Greek, and it survived into the age of jazz and scandal. The British took Alexandria in 1882, with Gladstone arranging his own atrocities on Ottoman soil: Mansel considers it a crime, but it kept the party going for another 70 years. Beirut, not coincidentally, was a largely French affair, managed down to our own times by a spluttering clockwork of communal checks and balances.

Whatever the official status of these Levantine ports, it is fair to describe them, in their heyday, as city states. They were not melting-pots, quite: Levantines could share a common interest in trade, and managerial values; they could send their children to be educated in the schools that sprang up to receive them – Victoria College, in Alexandria, was the Eton of the Levant – but they were never bound to an overarching ideal, and there was often another home for them – the Benakis in Athens, or the Barkers in England – to where they could run in times of trouble, or to whom they could appeal for aid and intervention.

In Alexandria Cavafy could write about homosexual love with a freedom that other European writers might have envied, but as the poet of nostalgia it was always the Greek millennia he mourned, set to end for his own city within 30 years of his death. Waiting for the barbarians did not mean troubling to learn their language, at least for Cavafy and his fellow Alexandrines, who preferred French to Arabic.

Yet if there were limits to the convivencia, it did constitute a unique society, for in no other cities in the world did Muslims, Christians and Jews live together for so long. For Ottomans, foreign travel was awkward and restricted: the ports were windows onto the West, freer than Istanbul, freer for rich foreigners than their own metropolitan centres.

The struggle between Greek and Turkish armies for control of Anatolia between 1919 and 1922 brought the whole system crashing down, and defined the terms by which Turkey would become a nation. The city states were caught in the riptide of 20th-century nationalism. Greek Smyrna ended in days of bloody violence, with 300,000 refugees desperately crowding onto the Cordon, begging the foreign ships to take them off. While they waited, preyed on by Turkish troops, the Greek area of the city burned. The Greek government was reluctant to help, and British and American warships had to wait for days before they received orders to evacuate the people.

It was a political decision to bring an end to Greek involvement in the region, followed in 1923 by the exchange of populations. Alexandria remained cosmopolitan, and subject to German air raids in the Second World War, but the status of its “foreign” population, like that of the king, who mingled with it, grew precarious. Egyptian nationalism swept the country after the Suez affair, and Nasser took control of the commerce, with predictable results. Ultimately the Eastern Mediterranean’s Jewish communities were undermined by the establishment of Israel, which joined forces with the various nationalists to drive them out.

Mansel draws us into the fascinating detail of fascinating lives as they were led in the Levantine cities: the parties, the prejudices, the higher politics. Levant brings second helpings of the treats he dished out in Constantinople, exercising the same gift for narrative, detail and analysis. He has mined the voluminous records, travelled and interviewed, to write what will remain for years to come the most authoritative and readable history of the Levantine world.

Jason Goodwin’s detective novel, ‘An Evil Eye’ is published by Faber & Faber