Pisa historical timeline

Pisa's history has a single shape: a city made rich by the sea, broken by a rival, absorbed by a neighbour, and left with the buildings its wealth had already paid for. Everything in the Piazza del Duomo was begun while Pisa was a Mediterranean power; almost nothing was added after it stopped being one. The university, founded in the middle of the decline, turned out to be the institution that lasted.

Chronology

1. 180 B.C. — Rome establishes a colony at Pisa, raising it to municipium status in 89 BC. The site is chosen for the same reason it always was: a river mouth with access to the sea. The Roman city is almost entirely buried beneath the medieval one, but the grid of the oldest streets near the Arno still follows it.
2. 11th century — Pisa reaches its height as one of the four great maritime republics, with trading reach across the Mediterranean and a fleet to enforce it. This is the wealth that pays for everything a visitor comes to see. Work begins on the cathedral, and the square it stands in is laid out on open ground outside the city walls — which is why the Piazza del Duomo feels detached from the town.
3. 1063 — Construction of the cathedral begins, in a style assembled from Pisa's own trading contacts: classical columns, Islamic-influenced inlay, blind arcading in striped marble. It becomes the template for Pisan Romanesque, which spreads through Tuscany, Corsica and Sardinia on the back of Pisan sea power.
4. 1152 — The baptistery is begun, circular and the largest in Italy. Its acoustic — a sung note sustains long enough to harmonise with itself — is still demonstrated aloud by the custodians several times an hour, and is the one thing in the square most visitors remember hearing rather than seeing.
5. 9 August 1173 — The campanile is begun. It starts to settle unevenly before the third storey is complete, because the subsoil is waterlogged silt. Construction stops and restarts repeatedly over two centuries, and those pauses are the reason the tower exists at all: each gave the ground time to consolidate under the weight already on it.
6. 1284 — The Genoese fleet destroys Pisa's at the Battle of Meloria, on the shoals now inside a marine protected area a few kilometres offshore. It is the end of Pisa as a naval power. The city does not recover, and in 1290 Genoa destroys the Porto Pisano for good, removing the harbour the republic was built on.
7. 1343 — The university is founded, in the middle of the decline rather than at the height. It proves to be the most durable thing the city ever created: it still dominates Pisa, and with the later Scuola Normale Superiore and Sant'Anna school it gives a town of under 100,000 an academic weight out of all proportion to its size.
8. 1372 — The campanile is finally completed, 199 years after the first stone and nearly a century after the republic that commissioned it had ceased to matter. The bell chamber at the top is visibly corrected against the lean — it was built to hang level on a tower that was not.
9. 1405 — Florence occupies Pisa, and the city becomes a provincial town in someone else's state. The practical consequence is architectural: the money stops, and the Piazza del Duomo is left as the complete late-medieval ensemble it still is, rather than being rebuilt in each subsequent fashion the way Florence was.
10. 1564 — Galileo Galilei is born in Pisa, and later teaches at its university. The association is the city's second identity and a genuine one: Pisa's self-image rests on its schools rather than its monuments, and the institutions it is proudest of are scientific.
11. 19th century — The lungarni, the embankment streets along the Arno, take their present form, and the city becomes a stop on the new Tuscan railways. That rail position is why Pisa later gets an airport inside the city and why it is today the arrival point for much of Tuscany rather than a destination in its own right.
12. 1944 — Fighting along the Arno in the Second World War damages the city heavily and a fire destroys the roof of the Camposanto Monumentale, melting its lead onto the frescoed walls below. The restoration of those frescoes has run for decades and is still in progress — which is why the Camposanto is both the quietest building in the square and the one most visibly still being worked on.
13. 1987 — The Piazza del Duomo is inscribed as a UNESCO World Heritage Site under cultural criteria i, ii, iv and vi. The first of those is the one that matters: it marks the ensemble as a masterpiece of human creative genius rather than merely an important example of something.
14. 7 January 1990 — The tower is closed to the public with its tilt at 5.5 degrees and genuine fear of collapse. Engineering work between 1993 and 2001 — soil extraction from the high side, counterweights, ground anchors — brings the lean back to 3.97 degrees.
15. 15 December 2001 — The tower reopens. The lean is now stable and monitored, and visits are rationed by timed slot, which is the form every visitor meets today: 251 steps, about thirty minutes, no one under eight, and no entry at all if you are late.