Build up a façade in layers: let the wall advance in stages towards the central bay, double the pilasters or columns as it advances, and break the entablature forward over every support.
Rules · Cities · Plans · Columns
The piazza as open arms
Before the mother church lay out an oval piazza enclosed by free-standing colonnades four columns deep, so that the church seems to embrace the faithful; set an obelisk at the centre and a fountain on each side along the cross axis, and join the oval to the church front by straight corridors.
Bernini explained the colonnades as the arms of the Church, reaching out to welcome Catholics, to bring heretics back and to show unbelievers the true faith. The arms are four columns deep, making three aisles with a wide central one for carriages, and carry an Ionic entablature, a balustrade and about 140 statues of saints. They enclose an oval about 240 m across, whose centre is the obelisk Fontana moved in 1586; Maderno’s fountain (1613) was matched by a second in the 1670s.
Between the oval and the basilica the straight corridors enclose a trapezoidal piazza that widens toward the church. The widening makes Maderno’s over-wide front look narrower and taller than it is.
Related rules
To unify a façade of two or more storeys, run a single order of pilasters or columns through all of them, from the base to the main cornice.
To combine the unity of a central plan with the direction a church needs, plan the space as an oval, set across the axis to widen the view of the altar, or along it to lead the eye towards it.
Let the wall of a façade curve in plan (concave, convex, concave) so that the front answers the street, the light and the space within, and the order bends with it.
Make the stair of a palace a processional space: one broad flight rising to a landing, then turning back in two flights either side to arrive at the principal floor beneath a single great vault.
Make the parterre oblong rather than square, since figures somewhat oblong look better on the ground than square ones; later practice made it as broad as the front of the house and about twice as long.
parterre oblong; later practice: width ≈ house front, length ≈ 2 × width
Cite this page Chris Paton, “The piazza as open arms”, The Textbook of Architecture, https://textbookofarchitecture.com/rule/bernini-oval-piazza. Text, drawings and models licensed under CC BY-NC 4.0.