Palazzo Piccolomini is the Renaissance palace on Banchi di Sotto, a few steps from Siena's Piazza del Campo, built for the family of Pope Pius II. Its rough stone walls look more like Florence than Siena. Inside are the State Archives of Siena, and their best-kept secret: the Biccherne, painted wooden covers that turned the city's tax ledgers into small works of art for over four centuries.
Palazzo Piccolomini at a glance
- Where: on Via Banchi di Sotto at the corner of Via Rinaldini, just north-east of the Piazza del Campo.
- Built: 1460 to 1495, for Giacomo and Andrea Piccolomini, nephews of Pope Pius II.
- By: Bernardo Rossellino, with sculptural work by Antonio Federighi and Urbano da Cortona.
- What it is today: home to the State Archives of Siena and the Biccherne museum, with documents going back more than a thousand years.
- Time needed: 10 minutes to look at the façade; about an hour if you visit the archives' museum.
A Florentine palace for a Sienese pope
Enea Silvio Piccolomini, a humanist from a Sienese family, became Pope Pius II in 1458 and set about leaving his family's mark on Siena and on his home village, which he rebuilt as Pienza. His nephews Giacomo and Andrea asked Bernardo Rossellino, the architect of Pius's palace in Pienza, for the designs of a city palace in Siena. Work began in 1460 and lasted until 1495. With its heavy rusticated stone, rows of mullioned windows and strong cornice, the building follows the Florentine model of Palazzo Medici Riccardi and Palazzo Rucellai, and stands out among Siena's brick Gothic houses.
In 1884 the Bank of Italy bought and refurbished the palace, and in the 19th century the architect Augusto Corbi painted neo-Renaissance decorations on the main floor. Today it holds the State Archives: around 60,000 parchments and records of the Republic of Siena, from 736 to the 20th century. A terrace on the upper floor looks over the medieval roofs to the cathedral, and a loggia at the very top looks out over the countryside.
What to look for
- The façade: rough-cut stone blocks, paired windows under round arches and a deep cornice, a Florentine Renaissance look rare in Gothic Siena.
- The Piccolomini arms: look for the family's emblem of five crescent moons on a cross, which the Piccolomini placed on their buildings across Siena and Pienza.
- The Biccherne covers: painted wooden panels made from 1258 to 1682 for the account books of the Biccherna, the city's finance office, and other offices, with a new one painted every six months.
- Famous panels: look for Francesco di Giorgio's Madonna of the Earthquake, and a cover showing Pius II making his nephew a cardinal.
- Palazzo Piccolomini-Clementini: the Gothic palace across the street, a good contrast with the Renaissance building.
Siena's tax books as art
The Biccherna was Siena's finance office from the 12th century until 1786. At the end of each six-month term, its officials paid a painter to decorate the cover of their account book, often with a religious scene, a coat of arms or an event of the day. Some of Siena's leading painters took the job, among them Giovanni di Paolo and Francesco di Giorgio. Most of the panels survived in the archives, although a few dozen were sold and are now in museums from London to Boston.
Tips for your visit
- Visits to the archives' museum are often by booking or guided tour, so check the State Archives website before you go.
- Look at the façade from across the street, near Palazzo Piccolomini-Clementini, to see the whole height of the building.
- Combine it with the Piazza del Campo: the palace is just behind the north side of the square.
- Come in the morning, before the lunchtime crowds fill Banchi di Sotto, one of Siena's main shopping streets.
Nearby
- Piazza del Campo: Siena's shell-shaped main square, home of the Palio horse race, a minute's walk away.
- Loggia del Papa: the open Renaissance loggia that Pius II built in 1462 in honour of his family, a short walk east where Banchi di Sotto becomes Via di Pantaneto.
- Palazzo Pubblico and the Torre del Mangia: the town hall with its museum and the tall tower on the Campo, a few minutes' walk.
- Loggia della Mercanzia: the merchants' loggia at the Croce del Travaglio, where Siena's three main streets meet.
See Siena with World City Trail
Our Siena scavenger hunt turns the city into a game you play on your phone. The route links 10 stops and takes around two hours, with about 24 minutes of walking. It includes Siena Cathedral, Santa Maria della Scala and the Pinacoteca Nazionale, all a short walk from Banchi di Sotto.
If you prefer a different format, there is also a self-guided walking tour and an outdoor escape game in Siena.
Play the Siena scavenger hunt →
Take the self-guided walking tour of Siena →
Play the outdoor escape game in Siena →
Facts checked in October 2026.