Construction began in 1562 for the Aldobrandini, a Florentine family that had risen to prominence in Rome and would soon supply the Church with Pope Clement VIII. The project was entrusted to Giacomo Della Porta, one of the leading architects of late-sixteenth-century Rome and a continuator of Michelangelo’s work at St Peter’s. Della Porta laid out the main block facing what is now Piazza Colonna, opposite the second-century Column of Marcus Aurelius, and designed the courtyard fountain that would become a model widely copied in later Roman palaces. Work was carried on after his death by Carlo Maderno, the architect of the facade of St Peter’s, who brought the building close to completion around 1580 within a restrained late-Renaissance idiom.

In 1659 the palace was purchased by the Chigi, a Sienese banking family whose fortunes had been transformed by the election of Fabio Chigi as Pope Alexander VII two years earlier. The family commissioned Felice Della Greca, an architect close to the Chigi circle, to extend and finish the building during the 1660s and into the following decades, adapting it to the scale and representational needs of one of Rome’s most powerful papal families. The palace took on its present name and, through successive Chigi generations, accumulated the libraries, antiquities and furnishings of a senior Roman princely household, much of which was later dispersed when ownership changed in the modern period.

After Italian unification the building entered public service. From 1878 it housed the embassy of Austria-Hungary, and in 1916 it was acquired outright by the Italian State, initially used for the Ministry for Colonial Affairs and subsequently for the Ministry of Foreign Affairs, which kept its headquarters there for several decades. In 1961 Palazzo Chigi was designated as the official seat of the President of the Council of Ministers and of the Council of Ministers itself, a function it retains today. The Sala del Consiglio dei Ministri, where the cabinet meets, and the adjoining state rooms are now among the principal ceremonial spaces of the Italian Republic, while the facade on Piazza Colonna has become one of the most recognisable institutional images of the country.