“CITIES are durable. Most last longer than the countries that surround them, or indeed any other human institutions. But some thrive, whereas others merely mark time (Cleveland, Minsk, Pyongyang), go into apparently long-term decline (Detroit, New Orleans, Venice) or disappear (Tenochtitlán, Tikal, Troy). What are the characteristics of a successful city? The short answer is good government and a flourishing economy. But such attributes may come and go in the life of a metropolis. In order to be continuously successful, a city has to be able to reinvent itself, perhaps several times.”

Harvard’s Edward Glaeser describes how Boston has done this three times—“in the early 19th century as the provider of seafaring human capital for a far-flung maritime trading and fishing empire, in the late 19th century as a factory town built on immigrant labour and Brahmin capital, and finally in the 20th century as a centre of the information economy.” On each occasion, human capital provided the secret to Boston’s rebirth. A strong base of skilled workers, writes Mr Glaeser, has been a source of long-run urban health.

Education was important from the first in Boston. But Mr Glaeser draws attention to other characteristics of the city that were present even in colonial times. It had a strong set of community organisations, because of its church structure, and something like the rule of law. It also had a tradition of “democratic egalitarianism”.

Law has been essential for urban life since Babylonian times, both because cities have usually been centres of commerce, and trade needs regulation, and because cities tend to draw different kinds of people, whose success in living together depends on common rules of behaviour. Democracy, too, has served cities well, providing a shock-absorber for changing economic times and a mechanism whereby immigrants can join the mainstream.

Immigration, or at least an ethnic and religious mix, has also been closely associated with urban success. As Joel Kotkin points out in “The City”, Chinese towns at the end of the first millennium AD showed the same cosmopolitan mixture as did Alexandria, Cairo, Antioch and Venice. Pre-1492 Seville, 16th-century London and 19th-century Bombay (now Mumbai) all contained a variety of different peoples, whether Muslims, Jews, Parsis or others.

Throughout history, cities open to the world have benefited both from an exchange of goods and from a trade in ideas from abroad. Japan, by closing its doors to foreigners, condemned its cities to slow marination in their own culture until the country’s opening up after 1853. Today the burgeoning cities with the best chance of overcoming their difficulties are those in Asia and Latin America that can gain from globalisation. Africa’s cities, largely excluded from this phenomenon, are winning relatively little investment, trade or entrepreneurial fizz from foreigners.

Some cities in the rich world, too, have been much more successful than others at exploiting globalisation. The ones that have done best are those that have plugged into global industries and been able to capture the headquarters or lesser corporate centres of globalised companies, especially banks and other financial firms, argues Saskia Sassen, of the University of Chicago. London, New York and Tokyo are pre-eminent in this, but some other cities—Paris, Frankfurt, Zurich, Amsterdam, Chicago, Los Angeles, Sydney, Hong Kong, São Paulo, Mexico City—are not far behind.

Not every city can “go global” or will even want to. There are other types of raison d’être. One is simply to be a pleasant place to live and work, pleasant meaning different things to different people, of course. In the developing world most people would be delighted to live in a city that was prosperous and well governed, if that meant jobs were available, officials were honest, the streets were safe, housing was affordable and transport, sanitation and basic utilities operated to minimum standards. Even in rich countries not all these things can be taken for granted.

Mercer, a consulting firm, publishes a ranking of big cities each year based on an assessment of about 40 factors falling into ten categories (political, economic, cultural, medical, educational, public-service, recreational, consumer-goods, housing and environmental). Last year the top ten cities were Zurich, Geneva, Vancouver, Vienna, Auckland, Dusseldorf, Frankfurt, Munich, Bern and Sydney.

The Economist Intelligence Unit, a sister organisation to The Economist, carries out a similar exercise (see table). Five of its top ten cities for 2005 were also in Mercer’s top ten. All ten in each list, with the exception of Sydney and Calgary, might be considered rather homely, even dull. The cities that have done most to excite attention the world over—New York, Chicago and Los Angeles—are also-rans. Smallish countries mostly do well, and Australia, the most urbanised country of all, ranks notably highly, at least in the EIU list.

No list includes the ability to reinvent itself among the desirable qualities of a city. That may, however, be increasingly put to the test, for some people believe that cities have had their day.”

Could the Church learn lessons from the histories of cities? If so, what might they be?