Bernini's colonnade, the open arms of St Peter's Square

The colonnade of St Peter’s Square is in every photo of the Vatican, and almost nobody really looks at it. It’s a portico of four rows of columns wrapped round the square, yes, but it’s also an optical machine built so that from two particular spots on the paving everything falls into place. For me it’s the Bernini you enjoy most without spending a penny. This is how I would approach it, with the official figures alongside.

Eleven years to embrace a square

Alexander VII, pope from 1655 to 1667, commissioned it, and the idea was largely his. On 31 July 1656 he asked Bernini for preliminary designs, and they were rejected one after another. After debate and changes, work started in March 1657, and the final design was settled between spring 1659 and spring 1660. The colonnade was complete in 1667, eleven years after the first brief.

The result is 284 columns and 88 pillars in four rows, in travertine and marble, under a pitched roof with a balustrade on top. The official sheet gives each portico a width of 16.77 metres and inner and outer lengths of 163 and 202 metres. The column height is a problem I’d rather tell you about straight. The Holy See says 13 metres and the Fabbrica di San Pietro says 16. Until they agree, I’m not giving you a number.

The intention, though, is clear. Bernini wrote that the colonnade should receive ‘with open arms’, like a mother, Catholics to confirm them in the faith, heretics to reunite them with the Church and unbelievers to enlighten them. That’s where the image of the square as an embrace comes from.

Where do the four rows line up?

It’s the best moment of the visit and it takes thirty seconds. Between the obelisk and each of the two fountains there’s a white marble disc inscribed ‘centro del colonnato’, marking the geometric centre of the curve in front of you. Stand on it and look. The four rows of columns hide behind the first, and the portico seems to be a single line.

From anywhere else the columns look endless and jumbled, and that contrast is exactly what Bernini was after. To see how everything is organised around the axis, start with the obelisk in St Peter’s Square, the point from which the ellipse was drawn.

140 saints looking down on the square

Along the balustrade stand 140 statues of saints, each a little over three metres tall, placed between 1662 and 1703, well after the columns were finished. They’re not random. The northern curve has defenders of the faith and founders of the oldest religious orders. The southern curve has popes, bishops, doctors of the Church and reformers. The straight arms carry martyrs, saints of the Catholic Reformation and those venerated as wonder-workers.

On the projecting sections are six coats of arms of Alexander VII, the paying client’s signature. And there’s something you can’t see. Bernini planned a third arm closing the square on the city side. The pope’s death in 1667 stopped the work and it was never built, so the square stayed open towards Rome, a gap the 20th century finally finished off with Via della Conciliazione.

The two straight wings

Where the colonnade meets the facade, two straight wings 70 metres long join the basilica. On the right is the Constantine Wing. It runs from the Bronze Door to the Scala Regia and has always been the main way into the basilica and the palaces, the route of papal processions. The pope’s funeral cortege still uses it, and on 11 October 1962 the 2,498 bishops of the Second Vatican Council walked along it. At its end is Bernini’s statue of Constantine.

On the left is the Charlemagne Wing, with an equestrian statue of the emperor by Agostino Cornacchini from 1725. It now hosts exhibitions backed by the Vatican, and its lower floor holds offices and the Swiss Guard post for the Arch of the Bells, built by Giuseppe Momo in 1930. How to see the guards without getting in their way is on my Swiss Guard page.

The colonnade for practical travellers

Beyond the art, the colonnade gets things done. The basilica’s security check, run by the Italian police, is in the right-hand curve and builds queues in high season, and the porticoes let you wait in the shade. The left-hand curve houses the square’s Vatican Post office, open daily, and the Charlemagne Wing a little-known parapharmacy, which I describe with the rest on the Vatican pharmacy page.

One detail always gets me. Close to the Bronze Door, set in the paving, a stone bearing John Paul II’s arms shows where the gunman hit him on 13 May 1981, at 17:19, mid-audience. It’s easy to walk over it without noticing. Everything else about the square is gathered in my main guide to St Peter’s Square.