Siena, which still today fascinates and seduces the visitor, is a city that has preserved its distinctly Medieval flavour intact. The city we see today in fact took shape during the Middle Ages, when Siena embarked on its most ambitious building spree ever. Later architecture is nonetheless represented, and the Palazzo Chigi-Zondadari, built in the graceful, composed style of the 18th century, is one of its finest examples.
Facing onto Piazza del Campo, construction of Palazzo Chigi-Zondadari was started in 1726 by order of Cardinal Antonio Felice Zondadari. Although of Senese descent, the cardinal lived in Rome and would often return to Siena to rest in his villa at Ancaiano.
The Roman architect Antonio Valeri designed the palazzo. Valeri had acquired a certain fame after winning a competition under Pope Clement XI to design a new sacristy for St Peter’s in Rome, where he had submitted two projects. With the pope’s sudden death the project was abandoned, however. Records indicate that the foundations of the palazzo in Siena were laid in 1724 and that by October 1726 the building was already half finished. It would appear that the building site was run by another architect, however - a man named Pietro Hustini – around whose origins there is some doubt. Although officially from Rome, some scholars believe Hustini could have been in fact a Frenchman who had come to the Papal capital to study architecture and who had remained in the city.
A number of problems plagued the building of the palazzo, which is one of Siena’s largest. A 1297 statute dictating the parameters of buildings looking onto Piazza del Campo placed considerable limitations of height and style on new buildings. The result is that despite its scale Palazzo Chigi-Zondadari is restrained in appearance, fully in harmony with the neighbouring Palazzo Sansedoni and Palazzo Piccolomini.
The Siena Biblioteca Comunale, or council library, contains the original plans for Palazzo Chigi-Zondadari. As well as the plans for the building we see facing onto Piazza del Campo today, the documents also contain details of another building erected at the same time by one of Siena’s most important 18th century architects, Jacopo Franchini. On the basis of this evidence, some experts have put forward the theory that Franchini may have also had a hand in the construction of Palazzo Chigi-Zondadari.