As modern people, we are used to the main roles cities play in the modern world, some of which are shared by pre-modern cities, and some of which are not. Modern cities are huge production centers, containing in them both the majority of the labor and the majority of the productive power of a society; this is very much not true of pre-modern cities – most people and most production still takes place in the countryside, because most people are farmers and most production is agricultural. Production happens in pre-modern cities, but it comes nowhere close to dominating the economy.

The role of infrastructure is also different. We are also used to cities as the center-point lynch-pins of infrastructure networks – roads, rail, sea routes, fiber-optic cable, etc. That isn’t false when applied to pre-modern cities, but it is much less true, if just because modern infrastructure is so much more powerful than its pre-modern precursors. Modern infrastructure is also a lot more exclusive: a man with a cart might visit a village where the road does not go, but a train or a truck cannot. The Phoenician traders of the early iron age could pull their trade ships up on the beach in places where there was no port; do not try this with a modern container-ship. Infrastructure is largely a result of cities, not their original purpose or cause.

So what are the core functions of a pre-modern city? I see five key functions:

1. Administrative Center. This is probably the oldest purpose cities have served: as a focal point for political and religious authorities. With limited communications technology, it makes sense to keep that leadership in one place, creating a hub of people who control a disproportionate amount of resources, which leads to
2. Defensive/Military Center. Once you have all of those important people and resources (read: stockpiled food) in one place, it makes sense to focus defenses on that point. It also makes sense to keep – or form up – the army where most of the resources and leaders are. People, in turn, tend to want to live close to the defenses, which leads to
3. Market Center. Putting a lot of people and resources in one place makes the city a natural point for trade – the more buyers and sellers in one place, the more likely you are to find the buyer or seller you want. As a market, the city experiences “network” effects: each person living there makes the city more attractive for others. Still, it is important to note: the town is a market hub for the countryside, where most people still live. Which only now leads to
4. Production Center. But not big industrial production like modern cities. Instead it is the small, niche production – the sort of things you only buy once-and-a-while or only the rich buy – that get focused into cities. Blacksmiths making tools, producers of fine-ware and goods for export, that sort of thing. These products and producers need big markets or deep pockets to make end meet. The majority of the core needs of most people (things like food, shelter and clothes) are still produced by the peasants, for the peasants, where they live, in the country. Still, you want to produce goods made for sale rather than personal use near the market, and maybe sell them abroad, which leads to
5. Infrastructure Center. With so much goods and communications moving to and from the city, it starts making sense for the state to build dedicated transit infrastructure (roads, ports, artificial harbors). This infrastructure almost always begins as administrative/military infrastructure, but still gets used to economic ends. Nevertheless, this comes relatively late – things like the Persian Royal Road (6th/5th century BC) and the earliest Roman roads (late 4th century BC) come late in most urban development.

Of course, all of these functions depend, in part, on the city as a concentration of people, but what I want to stress […] is that in all of these functions the pre-modern city effectively serves the countryside, because that is still where most people are and where most production (and the most important production – food) is. The administration in the city is administering the countryside – usually by gathering and redistributing surplus agricultural production (from the countryside!). The defenses in the city are meant to defend the production of the countryside and the people of the countryside (when they flee to it). The people using the market – at least until the city grows very large – are mostly coming in from the country (this is why most medieval and ancient markets are only open on certain days – for the Romans, this was the “ninth day”, the Nundinae – customers have to transit into town, so you want everyone there on the same day).

(An aside: I have framed this as the city serving the economic needs of the countryside, but it is equally valid to see the city as the exploiter of the countryside. The narrative above can easily be read as one in which the religious, political and military elite use their power to violently extract surplus agricultural production, which in turn gives rise to a city that is essentially a parasite (this is Max Weber’s model for a “consumer city”) that contributes little but siphons off the production of the countryside. The study of ancient and medieval cities is still very much embroiled in a debate between those who see cities as filling a valuable economic function and those who see them as fundamentally exploitative and rent-seeking; I fall among the former, but the latter do have some very valid points about how harshly and exploitatively cities (and city elites) could treat their hinterlands.)

Consequently, the place and role of almost every kind of population center (city, town or castle-town) is dictated by how it relates to the countryside around it (the city’s hinterland; the Greeks called this the city’s khora (χώρα)).

Bret Devereaux, Collections: The Lonely City, Part I: The Ideal City”, A Collection of Unmitigated Pedantry, 2019-07-12.