Pienza is considered the embodiment of the Renaissance utopia of the ideal city: obtained the recognition of a UNESCO site in 1996, it still communicates to the world the urban canons of the Renaissance for the rational organization of the spaces and perspectives of sixteenth-century squares and palaces. Pienza was wanted by Pope Pius II, hence the name that binds it to Aenea Silvio Piccolomini, who, having become Pope in 1458 with that name, wanted to rethink the native village by refining its renovation to Bernardo di Matteo Gambardelli called rossellino, a pupil of the famous Leon Battista Alberti, architect and scientist of his sequel. The works that took place there between 1458 and 1462 concerned the ancient village that legend has it founded by the soldier Syllable Corsinio. The geometric perspectives, the impressive volumes of the Cathedral and the Piccolomini palace, the accurate filling of the spaces in the center of the old medieval village represented a remarkable testimony of the architectural genius of the time.

The co-cathedral of Santa Maria Assunta or Duomo di Pienza represents a rare and delicate balance of Gothic and Renaissance forms and, inside, the Marian theme, very dear to the pontiff, is developed starting from the best names of the Sienese school. The complex, which stands on the site of the ancient parish church of Santa Maria, but oriented in a different way, was designed to be scenographically placed in the main square of the town. The interior is divided into three naves by two rows of pillars with leaning half-columns and decorated capitals, raised above the pillars. The apse is instead divided into three chapels, and the largest houses the choir. The other two chapels, formed by the arms of the cross, each have a large window. Singular is the fact that in the left side aisle, inside a niche, there is a pipe organ, from the seventies, with electric transmission.

Palazzo Piccolomini, also known as the Papal Palace, is considered the work of Bernardo Rossellino, inspired by the Palazzo Rucellai by the master Leon Battista Alberti. With a square plan, in stone worked in ashlar, it stands on three floors. The windows of the building, with pilasters and columns are divided in some cases by the family coats of arms in stone but with the apostolic insignia in gold and silver. Inside the building there is a small rectangular courtyard with a loggia and a garden, built according to the dictates of the Renaissance.

To complete the closure of the central square of Pienza, Palazzo Borgia, in front of Palazzo Piccolomini and so called because it was donated by the Pope born in Pienza to Cardinal Rodrigo Borgia, at the time his close collaborator, who became Pope Alexander VI and who made it your residence. Even today, the ancient Corsignano restores intact the imprint of a Pope, defender of Christianity and devotee of Mary, whose story, narrated in images, is visible for the traveler in Siena, in the Piccolomini Library, inside the Cathedral.