My visits to Heuneburg and Haithabu/Hedeby reminded me that I don’t know enough about one of the great puzzles in world history: why cities spread so slowly, with frequent retreats and abandonments. There were towns in the Balkans before the Indo-Europeans came, but it was almost the year 1,000 before there was a single town on the Baltic, and that was burned and abandoned. Why did it take 5,000 years for cities to spread from Mesopotamia to Denmark, when other innovations spread in a few centuries? And why did many societies which once had prosperous cities give them up?
The great obstacle to answering this question is that societies which give up cities tend to give up archives and the custom of writing down their literature at the same time. Without texts before, during, and after the abandonment it is hard to understand what happened in human terms. For the abandonment of most cities in the eastern Mediterranean around 1200 BCE we have whatever tablets happened to bake when the cities burned, and propaganda from the one Great King whose kingdom survived intact; for the end of civilization in the British Isles in the fifth and sixth centuries we have the oral traditions preserved by Gildas and the Venerable Bede who wrote long after the cities had waned and vanished.
Anthropologists, with their sympathy for small-scale societies, tend to point out that adopting sedentary life and the state did great damage, but it seems to me that once a society adopted intensive farming the damage was already done. Cities were often unhealthy, but many people still chose to live in them, and they were in a better place to make that choice for themselves than we are to make it for them. Moreover, cities could be a force for equality, since their populations were packed densely enough that large communities could govern themselves. As a military historian I can’t help but remember that cities attract predators, but few predators kill everyone, and in some cases it is clear that the survivors chose not to rebuild. Systems theorists often point out that cities depend on complex networks of trade and specialization which are vulnerable to disruption, but successful cities have been founded at the end of bandit-plagued roads and pirate-infested voyages, and the old idea that most ancient cities were artificial “consumer cities” which depended on outside taxes and tribute to sustaint themselves is no longer accepted by specialists.