Also on the Piazza del Campo stands the elegant Palazzo Piccolomini, whose main façade can be admired from Via Banchi di Sotto, at number 53.

As you can see, it is the only Renaissance building in the old town and, since the late 19th century, it has housed the Museo dell'Archivio di Stato di Siena, where priceless documents are kept.

The building began according to a design by Bernardo Rossellini under the architect Pietro Paolo del Porrina. Work began in 1469 and ended in 1510, whereas the Palazzo was the residence of the Piccolomini family, who were related to Pope Pius II. Not surprisingly, Rossellini was a favourite architect of the Pope, so he also built another palace for him a little more than 50 kilometres south of here, in Pienza.

This palace was the residence of noble Sienese, as the Piccolomini have been one of the most important families of Tuscany since the 12th century. They were bankers to the Roman Curia in Rome, with the result that they not only earned large sums of money and land, but were also exempt from building taxation.

Its exterior is harmonious and well balanced. Its ornaments, its façade in Tuscan stone, its windows with their curious ledges, etc. And to top it off, the sculptor Lorenzo di Mariano, Il Marrina, sculpted the capitals of the columns in the inner courtyard. Undoubtedly, it is a great building that many compare to the Palazzo Rucellai in Florence.

Already in the 17th century, owing to the disappearance of the Piccolomini family, the palace played different roles in the life of Siena: a school where aristocrats were taught, then the Escola Pia and, eventually, it passed into state hands in the 19th century and ended up becoming the museum that is here today.

If you decide to enter the museum, among the jewels you can see, you must not miss the collection of Tavolette di Bicherna and Gabella. They are 103 panel paintings that were used as covers for the official books of Siena. These works of art were created by the most renowned artists of Siena from the 13th century to the end of the 17th. Quite a relic.