Fabio Chigi, a member of the illustrious Sienese banking family of Chigi and a great-nephew of Pope Paul V (1605–1621), had been privately tutored and eventually received doctorates of philosophy, law, and theology from the University of Siena.

He began his apprenticeship in 1627 as vice-papal legate at Ferrara, and on recommendations from two cardinals he had been appointed successively Inquisitor of Malta and nuncio in Cologne (1639–1651).

There, he supported Urban VIII's condemnation of Jansenius' Augustinus by the papal bull In eminenti of 1642.

Though expected to take part in the negotiations which led in 1648 to the Peace of Westphalia, he had declined to deliberate with persons whom the Catholic Church considered heretics, and had protested, when it was finally completed, against the Treaty of Westphalia that ended the Thirty Years' War (1618–1648) and established the balance of European power that is to last until the wars of the French Revolution (1789).

Pope Innocent X had recalled Chigi to Rome and subsequently made him Cardinal Secretary of State and Cardinal-Priest of Santa Maria del Popolo.

After Innocent dies in January, 1655, Chigi, the candidate favored by Spain, is elected pope after eighty days in the conclave, on April 7, 1655, taking the name of Alexander VII.

The Church of Saint Andrew's at the Quirinal (Italian: Sant'Andrea al Quirinale, Latin: S. Andreae in Quirinali), a Roman Catholic titular church in Rome, is built for of the Jesuit seminary on the Quirinal Hill.

The site had previously accommodated a sixteenth century church, Sant'Andrea a Montecavallo.

Commissioned by Cardinal Camillo Francesco Maria Pamphili, with the approval of Pope Alexander VII, Sant'Andrea is the third Jesuit church constructed in Rome, after the Church of the Gesù and Sant'Ignazio.

It is to serve the Jesuit novitiate, which had been founded in 1566.

An important example of Roman Baroque architecture, Sant'Andrea has been designed by Gian Lorenzo Bernini with Giovanni de'Rossi.

Bernini had received the commission in 1658 and the church is constructed by 1661, although the interior decoration will not be finished until 1670.

Bernini considers the church one of his most perfect works; his son, Domenico, will recall that in his later years, Bernini spent hours sitting inside it, appreciating what he had achieved.

The main façade of the church faces onto the Via del Quirinale (formerly the Via Pia), as does Borromini's San Carlo alle Quattro Fontane further down the road.

Unlike San Carlo, Sant’Andrea is set back from the street and the space outside the church is enclosed by low curved quadrant walls.

An oval cylinder encases the dome, and large volutes transfer the lateral thrust.

The main façade to the street has an aedicular pedimented frame at the center of which a semicircular porch with two Ionic columns marks the main entrance.

Above the porch entablature is the heraldic coat of arms of the Pamphili patron.

The Jansenist school at Port-Royal is condemned and closed down in 1661 in the midst of the gathering theological storm that is to become known as the formulary controversy; those involved with the school have to sign a 1656 papal bull condemning the teachings of Jansen as heretical.

The final letter from Pascal, in 1657, had defied the Pope himself, provoking Alexander VII to condemn the letters, but that doesn't stop all of educated France from reading them.

Alexander VII's pontificate has been shadowed by continual friction with Cardinal Mazarin, advisor to Louis XIV of France, who had opposed him during the negotiations that led to the Peace of Westphalia and who defended the prerogatives of the Gallican Church.

During the conclave he had been hostile to Chigi's election, but was in the end compelled to accept him as a compromise.

However, he prevented Louis XIV from sending the usual embassy of obedience to Alexander VII, and, while he lived, foiled the appointment of a French ambassador to Rome, diplomatic affairs being meantime conducted by cardinal protectors, generally personal enemies of the Pope.

In 1662, the equally hostile Duc de Crequi had been made ambassador.

By his abuse of the traditional right of asylum granted to ambassadorial precincts in Rome, he had precipitated a quarrel between France and the papacy, which resulted in Alexander VII's temporary loss of Avignon and his forced acceptance of the humiliating treaty of Pisa in 1664.

Alexander has also encouraged architecture, and the general improvement of Rome, where houses have been razed to straighten and widen streets and where he has had the opportunity to be a great patron for Gian Lorenzo Bernini: the decorations of the church of Santa Maria del Popolo, titular churches for several of the Chigi cardinals, the Scala Regia, the Chair of St. Peter in the Vatican Basilica.

In particular, he has sponsored Bernini's construction of the beautiful colonnade in the piazza of St. Peter's Basilica.

He dies in May, 1667, and is memorialized in a spectacular tomb by Bernini.

The Barberini family's influence had peaked with the election of Cardinal Maffeo Barberini to the papal throne in 1623, as Pope Urban VIII.

Their urban palace, the Palazzo Barberini, (completed in 1633 by Bernini), today houses Italy's Galleria Nazionale d'Arte Antica (National Gallery of Ancient Art).

Giulio Rospigliosi had worked closely with Pope Urban VIII (1623–1644), a Barberini Pope, where he had worked in the Papal diplomacy as nuncio to Spain, among other posts.

An accomplished man of letters, who writes poetry, dramas and libretti, as well as what may be the first comic opera.

During the reign of Pope Innocent X (1644–55), who had been hostile to the Barberini and their adherents, Rospigliosi, made vicar of Santa Maria Maggiore in Rome, had continued his appointment as papal nuncio to the court of Spain.

After the accession of Pope Alexander VII (1655–67), he once again enjoyed papal favor.

In 1657 he had been named Cardinal-Priest of San Sisto and Secretary of State.

After Alexander VII's death in June 1667, an eighteen-day papal conclave concludes with Rospigliosi's election as Pope.

Upon his succession, he takes the name Clement IX.