Discover Ponte Sisto

Ponte Sisto crosses the Tiber between Via dei Pettinari in the Rione of Regola and Piazza Trilussa in Trastevere. Turismo Roma describes it as having a postcard backdrop in which the Dome of Saint Peter's can be made out. It is restricted to pedestrians, free, and open at all hours.

It was built for a Jubilee, because of a disaster at the previous one. Turismo Roma credits it to Sixtus IV della Rovere (1471–1484) for the Jubilee of 1475, to connect Piazza Trilussa and the Vatican with the rest of the city. The reference work gives construction as 1473 to 1479 and records, from Mandell Creighton's History of the Papacy, that Sixtus was mindful of the disaster of the Jubilee of 1450, caused by crowding on the Bridge of Sant'Angelo — then the only available means of communication with Saint Peter's. The same account says the bridge was built of blocks from the Colosseum.

There was a Roman bridge here first, and the sources differ about its end. Turismo Roma says it was built perhaps by Agrippa, son-in-law of Augustus, dating to 12 BC, and that in 147, after restorations under Antoninus Pius, it was identified as the Pons Aurelius or Pons Antonini. Turismo Roma then has it gravely compromised by the Tiber flood of 792 and called Ponte Rotto, the broken bridge, until the rebuilding of 1473. The reference work instead dates the destruction to 772, when the Lombard king Desiderius took Rome.

The hole in the middle is structural. Turismo Roma records four arches faced in travertine, a circular opening at the centre and five papal coats of arms in marble. The reference work explains the opening — the oculus, lightening the masonry of the central spandrel — as erected to diminish the river's pressure on the bridge in case of flood.

Nobody is sure who designed it. The reference work names Baccio Pontelli. Turismo Roma says the problem remains unresolved and that the Vasarian attribution to Pontelli has fallen, because he reached Rome only after the bridge was built.

The 19th century widened it and the 21st undid that. In 1877 two metal walkways on corbels were added along the flanks to Angelo Vescovali's design; the soft iron and cast iron deteriorated beyond maintenance, and in 2000 Gaetano Miarelli Mariani removed them and built new parapets, returning the bridge to its fifteenth-century appearance.

Four arches, and a hole that is doing work. Turismo Roma records Ponte Sisto as four arches faced in travertine with a circular opening at the centre and five papal coats of arms in marble. The reference work explains that opening: the oculus, lightening the masonry of the central spandrel, was erected to diminish the river's pressure on the bridge in case of flood. The spandrel is the solid triangle of masonry above the pier, which in flood is exactly what the water piles against — so it was pierced.

It stands on Roman piers. The reference work records that the builder reused the foundations of a prior Roman bridge, the Pons Aurelius, destroyed in the early Middle Ages. Turismo Roma dates that bridge to 12 BC, built perhaps by Agrippa.

Its authorship is an open question. The reference work gives the design to Baccio Pontelli. Turismo Roma states the identification remains unresolved, the Vasarian attribution having fallen because Pontelli arrived in Rome only after the bridge was built.

What you are looking at is a reconstruction of an appearance, not a survival of one. The 1877 widening added two metal walkways on corbels by Angelo Vescovali, in soft iron and cast iron that deteriorated beyond repair. In 2000 Gaetano Miarelli Mariani removed the nineteenth-century metal structures and made new parapets, restoring its fifteenth-century appearance partly with original travertine elements. The parapets you lean on are new; some of the stone in them is not.

The inscriptions are copies and the sources differ on why. The reference work: copies on the left bridge head, the originals removed in the 1990s after continued vandalism, the text composed by Bartolomeo Platina. Turismo Roma: removed to preserve them from the ravages of time, with the texts transcribed on the new parapets facing via Giulia.

It was built quickly, for a deadline, out of someone else's building. The reference work dates construction 1473 to 1479; Turismo Roma ties it to the Jubilee of 1475. Creighton's History of the Papacy, as the reference work reports, says the bridge was built of blocks from the Colosseum.

The hard part was already in the river. Rather than sink new piers in the Tiber, the builders reused the foundations of the prior Roman bridge — which is why a 15th-century bridge sits on a 1st-century BC alignment.

The design decision that matters is a subtraction. The oculus was cut through the central spandrel to diminish the river's pressure on the bridge in case of flood — removing material from the place where a flood exerts most force, on a site where the previous bridge had been destroyed by water or war.

The motive was a body count. Sixtus was mindful of the disaster of the Jubilee of 1450 through the crowding of the Bridge of Sant'Angelo, then the only available means of communication with Saint Peter's. A second crossing was a safety measure for pilgrim traffic.

The one thing nobody can settle is who drew it. The reference work names Baccio Pontelli; Turismo Roma says that attribution has fallen because he reached Rome only after the bridge was built, and the author is still unresolved.

Is there a charge? No. It is a public bridge with no ticket and no hours, and it is restricted to pedestrians.

What is the hole in the middle for? The oculus lightens the masonry of the central spandrel and was erected to diminish the river's pressure on the bridge in case of flood.

Who built it? Pope Sixtus IV della Rovere, for the Jubilee of 1475; the reference work gives construction as 1473–1479.

Who designed it? Unsettled. The reference work says Baccio Pontelli. Turismo Roma says that attribution has fallen because Pontelli reached Rome only after the bridge was built, and the author remains unresolved.

Why was it built? The reference work records, from Creighton, that Sixtus was mindful of the disaster of the Jubilee of 1450 through the crowding of the Bridge of Sant'Angelo, then the only available means of communication with Saint Peter's.

Is it true it was built from the Colosseum? The reference work reports Creighton's History of the Papacy as stating that the Sistine Bridge was built of blocks from the Colosseum.

What was here before? A Roman bridge, built perhaps by Agrippa and dating to 12 BC, identified after restorations under Antoninus Pius in 147 as the Pons Aurelius or Pons Antonini. Note that Antoninus restored and renamed it — he did not build it.

When was it destroyed? The sources differ: 772, when the Lombard king Desiderius took Rome, says the reference work; the Tiber flood of 792, says Turismo Roma. It was then called Ponte Rotto until 1473.

How long should I allow? Ten minutes.