Siena
How Siena was built and evolved over time
A city made of its own ground
Siena is built almost entirely of brick fired from the local clay, and that is why the whole city reads as one warm red-brown from any viewpoint. The colour was distinctive enough to become a pigment name: terra di Siena, burnt and raw sienna, is this ground. Stone appears where the city wanted to make a point — the cathedral's banded marble, the Palazzo Pubblico's lower storey — and brick everywhere else, which is a statement about hierarchy as much as about cost.
The square as a constitution
Work on the Palazzo Pubblico began in , and Piazza del Campo was laid out around it as a shell-shaped slope falling towards the building. The paving is divided into nine segments, one for each member of the Council of Nine who governed the republic at its height, which makes the floor of the square a diagram of who was in charge. The Torre del Mangia rises from the palazzo, built to the same height as the cathedral's campanile so that civic and religious power stood level — an argument conducted in masonry.
The cathedral, and the nave that was never built
The Duomo is banded black and white marble, with an inlaid marble floor of fifty-six panels and sculpture by Nicola and Giovanni Pisano, Donatello, Michelangelo and Bernini. In the republic began something far larger: the Duomo Nuovo, an enormous new nave running at right angles to the existing church, which would have been reduced to a transept of the biggest cathedral in Christendom.
The Black Death of 1348 ended it. The project was abandoned at the point construction had reached, and that point is still standing: the Facciatone, a facade wall and one aisle, open to the sky, with a staircase inside it that visitors climb for the best view in Siena. No other Italian city displays the cost of the plague so directly — it is a building stopped mid-sentence.
Ridges, terzi and steps
Siena occupies three clay ridges meeting near the centre, which is why it divides into three terzi and why the streets climb and fall constantly. Building on clay ridges also means retaining walls, vaulted substructures and sudden drops: several streets run above vaulted undercrofts, and the medieval hospital of Santa Maria della Scala descends through multiple levels into the slope below the cathedral square.
Frozen in 1555
The end of the republic in is the reason all of this survives. A conquered provincial town has neither the revenue nor the motive to rebuild its centre in each new fashion, so Siena never received the Renaissance and Baroque overwriting that Florence and Rome did. The medieval city stands because the city that would have replaced it never had the money.