Piazza Pio II is named after Aeneas Silvius Piccolomini, a prince of the Church and a refined humanist, a man of letters and a lover of the arts, who took a particular interest in architecture. He commissioned Bernardo Rossellino to build Pienza, which had been known in the Middle Ages as Corsignano.
Pius II and Rossellino worked cheek by jowl on renovating Corsignano in order to turn it into a jewel of Renaissance town-planning subsequently promoted to the rank of city and rechristened Pienza by order of the Pope. Rossellino, who was born in Settignano in 1409 and died, like Pius II, in 1464, was a follower of Leon Battista Alberti, having worked with him on Palazzo Rucellai in Florence.
The urban renewal plan for Pienza was implemented fairly rapidly, between 1459 and 1462, thanks to the munificence of the Pope and of the cardinals and court dignitaries whom Aeneas Silvius ordered to build their palazzi in the new city.
The medieval square with its Romanesque church of Santa Maria was swept away to make room for the first “ideal city” envisaged by the ancients and then by the humanists, so that the ratio politica would be perfectly reflected in the new urban arrangement.
The heart of the new scheme was a trapezoidal square paved with a stone grid enclosing large rectangles of red brick, surrounded by monumental buildings representing the new city’s religious, political and private powers: the Cathedral and Bishop’s Palace, the Town Hall and Palazzo Piccolomini, the Pope’s family residence. But the real protagonist here is man who, standing in the white travertine circle in the middle of the square, becomes the unit of measurement, the true yardstick, of all the surrounding buildings.
The shadow of the Cathedral façade which, on the basis of the Julian calendar then in force, sits perfectly within the square’s grid pattern at midday on the day of the spring equinox and the summer solstice, is an expression of the multifaceted interests of Renaissance man, a student of the humanities but also of the sciences.