Why old towns are built high, and what happens when the reason goes

A great many old towns sit somewhere inconvenient. On a ridge above the farmland they work. On a defensible spur with a difficult approach. Halfway up a slope where every load of water and firewood has to be carried.

Nobody would build there now. The reasons they did are worth setting out, because they explain a lot of what these places look like — and because the disappearance of those reasons explains what is happening to them.

Defence

The most obvious. Height is an enormous military advantage against pre-industrial weapons, and a difficult approach multiplies the value of a small number of defenders.

In regions with a long history of raiding — coastal Mediterranean areas subject to seaborne raids, frontier zones, valleys with a history of feuding — settlements moved uphill and clustered tightly. The dense, inward-facing plan of many hill towns, with narrow streets and blank outer walls, is a defensive form.

The pattern shifts when the threat ends. In several regions there is a documented movement downhill from the nineteenth century onward, as security improved and the cost of the elevated position stopped being worth paying.

Not building on the good land

An underrated factor. Arable land is finite and it is not where you want houses.

Building on the rocky ridge preserves the valley floor for cultivation. In regions where farmland is scarce and steep, this is not sentiment — it is the difference between a settlement that can feed itself and one that cannot.

The terracing that surrounds many of these towns represents an extraordinary investment of labour, built up over generations, and the settlement sits above it precisely so as not to occupy it.

Water, disease and air

Lower ground in many regions meant standing water, and standing water meant malaria. In substantial parts of the Mediterranean, coastal plains were seriously malarial until drainage programmes in the twentieth century, and populations sensibly lived above them and walked down to work.

The coastal settlement patterns of several countries changed dramatically once the disease was controlled — which is why so many stretches of coast have an old town on a hill and a modern town by the sea.

Elevation also gave cooler air in hot climates, and getting above valley fog and frost pockets mattered in cold ones. Cold air pools in valley bottoms, and a settlement partway up a slope can be several degrees warmer on a winter night than one at the base.

Springs

The constraint that decided many exact locations. A settlement needs reliable water, and the position of a spring line — where permeable rock meets impermeable and water emerges — determined where people could live.

This is why lines of villages appear at a consistent elevation along a slope. They are following the geology.

What changed

Four things, in roughly this order: security improved, malaria was controlled, mechanised transport made valley routes decisively cheaper, and agriculture stopped employing most of the population.

The last is the decisive one. A hill town's entire economic logic assumed that most inhabitants walked out to fields each day. Once agriculture mechanised and consolidated, the population that the town existed to house had no work, and the young left.

Road and rail follow valleys. Anything requiring vehicle access — a factory, a supermarket, a clinic — locates in the valley. The hill town becomes somewhere people commute out of, then somewhere they leave.

The present situation

Across southern Europe, parts of the Andes, Japan's mountain interior and elsewhere, upland settlements are losing population and have been for decades. The pattern is consistent: the young leave for work, the population ages, services close because there are not enough users, and the closure of services accelerates the departure.

Various responses have been tried. Some places have sold derelict houses for a nominal sum on condition of renovation. Some have pursued tourism, which brings money and tends to convert housing into holiday accommodation, producing a town that is full in August and empty in February. Some have attracted remote workers, which is recent enough that its effects are unclear.

None of these reverse the underlying arithmetic on their own, and the ones that have worked best generally involved something specific — a functioning local industry, a university, a genuinely year-round reason to be there.

What is lost

Not only buildings. Terraces collapse within a few decades without maintenance, and when they go, the slope goes with them — abandoned terracing is a recognised contributor to erosion and landslide risk.

Local knowledge goes: which spring runs in August, which slope holds snow, how to lay a dry stone wall that stands. That knowledge existed because it was used daily and it does not survive being written down.

And a settlement pattern that took a thousand years to work out disappears in about two generations, which is a strange thing to watch.