In 1459, Enea Silvio Piccolomini, who had just elected pope with the name of Pius II, decided to fulfil his greatest dream: to build a people-friendly town. Like a Plato of his time, Piccolomini's idea was that of an ideal city not as a point of arrival, but as a point of departure for a rebirth. This is how the transformation of his native village, Corsignano in the Val d'Orcia, began. He entrusted Bernardo Rossellino with the central square, the cathedral, the papal noble palace and the seat of the Town Hall and of the bishop of Pienza. The project soon became more extensive, and the buildings overlooking the main part of the village were also renovated. The buildings were designed according to Leon Battista Alberti's ideas. The facade of the Cathedral recaptures the tripartition adopted in the Malatesta Temple in Rimini.
Bernardo Rossellino designed the square, giving it a trapezoidal shape, tangential to the main street, at the point where the land stretches towards the Val d'Orcia. Located in the square, are the Cathedral and Palazzo Piccolomini. The Palazzo Vescovile (Episcopal Palace) is on the right and Palazzo Pretorio (Praetorian Palace) is on the left along the road. The Tuscan terracotta floor with squared traveritine strips, placed crosswise on it, creates a perspective of movement in harmony with the monumental buildings.