How Florence was built and evolved over time

The city's fabric is unusually consistent because its builders drew on the same quarries and the same handful of forms for centuries. Pietra forte, the hard sandstone from the hills south of the Arno, faces the great civic palaces and paves the streets; pietra serena, a softer grey stone, frames the doors, arches and columns of the interiors. The result is a city with a narrow colour range and an obvious family resemblance from one century to the next.

The dome

Santa Maria del Fiore was begun in the 1290s and its crossing stood open for generations because the span was beyond the available technique: too wide for conventional centring, too high to scaffold from the floor. Filippo Brunelleschi's solution, built between the 1420s and 1430s, raised a double shell in herringbone-laid brick that supported itself as it rose. It remains the largest masonry dome ever built, and it is the reason the city's skyline reads the way it does from every hill around it.

The palace as a type

The Florentine palace — a rusticated stone block around an internal courtyard, with the roughest masonry at street level and progressively finer work above — was effectively invented here in the fifteenth century and exported across Europe. Palazzo Vecchio's tower and the Signoria give the civic version; the merchant families gave the domestic one.

Rebuilt more often than it looks

The continuity is partly an illusion of good repair. The German army destroyed every bridge in the city except Ponte Vecchio in 1944, and the approaches to it were demolished with them; the 1966 flood then damaged much of what had been rebuilt. A great deal of what reads as medieval is medieval in form and postwar in fabric.