Borromini’s activity in Rome started in 1619, when he came to the Eternal City, to work as an insignificant assistant of then-valued architect, his uncle – Carlo Maderno.  He helped him in prestigious works, in building St Peter’s Basilica (San Pietro in Vaticani), Palazzo Barberini and the Church of Sant’Andrea della Valle.  After the death of his uncle, one of his peers, Gian Lorenzo Bernini became his supervisor – a sculptor who was famous in Rome, and was commissioned many construction works as well. Working by Bernini’s side became a life challenge for Francesco, on one side he saw the architectural shortcomings of his boss, while on the other hand, he was simply jealous of his fame, commissions and most of all recognition. In time Borromini also started to get commissions, although it was extremely laborious for him. Soon, he and Bernini would quarrel over the construction of a baldachin in the Vatican Basilica and this would be the beginning of a life-long rivalry.
Prior to this falling out, thanks to Bernini’s intercession, Francesco received the commission for the design of a university Church of Sant’Ivo alla Sapienza, which he would finish many years later. In 1641 he receives his first solo commission, a tiny, pressed into a corner of the street Church of San Carlo alle Quattro Fontane (1641). He fought for it like a lion, resigning from his salary, only to be allowed to display his exceptional architectonic talents.  He turns out to be an original, searching for new solutions designer, who uses dramatic, undulating lines and once receding once advancing plans. Yet despite arousing some interest his work is not appropriately valued.

Borromini’s lucky star starts shining after the death of Pope Urban VIII and the election as Holy Father in 1644 of his rival, meaning a client who did not favor Bernini – Innocent X. He mercilessly deals with his rival accusing him of failure in calculations in the construction of bell towers, which were to flank the façade of St Peter’s Basilica. Bernini is discredited, barred from further construction work, forced to pay damages for demolishing the already-constructed and threatening to collapse tower. Even though the designs submitted for this site by Borromini were not taken into consideration, the new pope made him his trusted architect.

The period of the pontificate of Innocent X is a time of intensified activity of Borromini (at that time his most important works are completed), unfortunately lasting only ten years. The election of the next pope, Alexander VII, in 1655 means once again an exaltation of Bernini. This time it is Borromini who is accused of architectonic failures, he is barred from the construction work on the prestigious Church of Sant’Agnese in Agone, which seemed to be an exhibitive example of his talent and abilities. As if this was not enough, it was Bernini, among others, who was called upon to finish his work.  From this moment a period of depression and melancholic attacks, which would continue until his death, begins in Borromini’s life. The frustrated architect no longer cares about fame, which brings him papal orders and income and which radiates outside of Italy, from where he receives many requests for designs. With hardship he works and finishes the buildings which he previously started, while Bernini becomes the pope’s right-hand man and together with him begins designing the new face of Rome.  Each exaltation of his rival is treated by Francesco as a personal defeat.  He does not marry, he has neither children nor friends. He lives the life of a loner, in which the reading of Seneca’s works and deep devotion to God, seem to be the only activities outside of architecture. He becomes even more angry and proud to his contemporaries.

In the summer of 1667 he pierces himself with a sword and after a few days of suffering, he dies. He is buried, just as he wished, in the tomb of his uncle Maderno, in the Church of San Giovanni dei Fiorentini. It is the same church where he was a parishioner and near which he lived after coming to Rome until the end of his days, where he completed his last works. His funeral is attended neither by priest nor by mourners as is often the case with suicides.

It was not until 1994 that Borromini was rehabilitated by the Church and only then a plaque with his surname was placed under the one devoted to his uncle.

Borromini was a great interpreter of the classical architecture, which he desired to give an original mark of his own talent. At the basis of his art, he saw the works of antiquity, the analysis of the architectonic form of Michelangelo (Michelangelo Buonarroti) and the observation of nature; these were the three pillars of his architectonic worldview. He took advantage of the glossary of antique forms, enriching them with artistic, even original elements, for which the scenery (very often due to a lack of funds) was white, undecorated walls. In this he was accompanied by absolute, uninhibited freedom in his choice of elements; those which were as a rule decorative in his designs became load-bearing, while those which were in principle load-bearing were used as ornaments.

In the end his vision dominated the architectural style of the next century, which we call rococo.  Borromini’s influence on the future generations in effect started immediately after his death. Similar thinking about architecture was adopted by Guarino Guarini, active in Torino, as well as subsequent generations of exceptional architects north of the Alps: Bernhard Fischer von Erlach, Lucas von Hildebrandt, or  Balthasar Neumann. 

Borromini’s most important buildings and works in Rome:

• Palazzo Barberini – oval staircase in the right wing of the palace
• Church of San Carlo alle Quattro Fontane (1634–1667)
• Palazzo Spada (1632) – perspective colonnade
• Church of Sant’Ivo alla Sapienza (1640–1660)
• Oratory of the Filippini (oratory of St. Philip Neri (1637)
• Palazzo Pamphilj (1644–1650) – Galleria Grande
• Church of San Giovanni in Laterano (1646–1649) – reconstruction and modernization of church interior in the spirit of Baroque
• Church of Sant’Agnese in Agone (1653)
• Church of Sant’Andrea delle Fratte – dome and bell tower
• Palazzo di Propaganda Fide (The College of the Propagation of the Faith) (1646–1667)
• Monastery complex (unfinished) at the Church of Santa Maria dei Sette Dolori on the Trastevere (Trastevere)
• Main altar in the Church of San Giovanni dei Fiorentini
• Spada Chapel in the Church of San Girolamo della Carità  (most likely)