NAME	YEARS	LUOGOPLACE	ITER
Attività nella Fabbrica di S. Pietro: con Maderno e, dal 1629, con Bernini, specialmente alla realizzazione tecnica del baldacchino	1624-1629	San Pietro in Vaticano	9
Palazzo Barberini (collaborazione tecnica con Bernini)	1629	Via delle Quattro Fontane	3
Galleria prospettica a colonne e scala a spirale di Palazzo Spada	1632-1636	Via Capodiferro	5
Palazzo dei Filippini (Torre dell'Orologio, Convento, Biblioteca, Oratorio…)	1637-1647	Piazza dell'Orologio (via della Chiesa Nuova)	5
Avvio ricostruzione del convento dei Trinitari e chiesa di S. Carlo Borromeo alle Quattro Fontane	1634-1639	Via XX settembre	3
Monumento Mellini, a Santa Maria Maggiore	1642	S. Maria Maggiore	3
Chiesa di S. Ivo alla Sapienza	1642-1660	Corso del Rinascimento	6
Chiesa e convento di Santa Maria dei Sette Dolori	1643-1649	Via Garibaldi, 27 (Gianicolo)	5
Palazzo Carpegna	1643-1649	Piazza Accademia di San Luca, 77 (vicino a via del Tritone)	3
Atrio e scalinata a palazzo di Spagna	1645-1648	Piazza di Spagna	7
Consulenze in palazzo Pamphili	1645-1650	Piazza Navona	6
Ampliamento di Palazzo Falconieri	1646-1649	Via Giulia	-
Restauro di S. Giovanni in Laterano	1647-1649	Piazza S. Giovanni	4
Collegio di Propaganda Fide	1652-1666	Piazza di Spagna	7
Direzione lavori chiesa di S. Agnese in Piazza Navona, iniziati da G. e C. Rainaldi	1653-1657	Piazza Navona	6
Abside e campanile S. Andrea delle Fratte	1653-1667	Via S. Andrea delle Fratte, 1 (vicino a Via del Tritone)	3
Pavimento e monumenti funerari di San Giovanni in Laterano	1656-1657	Piazza S. Giovanni	4
Restauro esterno del Battistero Lateranense	1657	Piazza S. Giovanni	4
Lavori in Palazzo Giustiniani (Sala delle Colonne)	1656-1659	Piazza della Rotonda	-
Rifacimento S. Giovanni in Oleo	1658	Porta Latina	8
Biblioteca Alessandrina	1659-1661	presso S. Ivo alla Sapienza vicino a Piazza S. Eustachio	6
Sistemazione della facciata del convento dei Trinitari	1660-1665	Via XX settembre	3
Cappella Falconieri	1664-1667	S. Giovanni dei Fiorentini	9
Definitivo prospetto della chiesa S. Carlo Borromeo alle Quattro Fontane	1665-67	Via XX settembre	3

Borromini came to Rome in 1624 to work with Carlo Maderno. The period in which he was most active goes from 1644 to 1655. His father, Giovanni Domenico Castelli, a modest architect that worked for the Visconti family, started him to stone-masonry; Francesco Castelli (that changed his surname to Borromini when he was just 28), still very young (around 1608) was sent to Milan , and stayed there until 1614 (1624 according to other sources) when he left the Lombard metropolis to come to Rome . Here he was kindly received by Carlo Maderno, fellow townsman and relative on the mother side, and by him employed on the works for the Fabbrica di San Pietro (iter 9) with the humble task of marble carver, to the extent that only in 1625 his name appears preceded by the title of Master. After Maderno's death (1629), Borromini continued working in San Pietro under Bernini's direction, especially in the technical execution of the baldachin, reproducing and developing on a larger scale the sculptor's designs. Already then there were some misunderstandings between the two artists; the disagreement became sharper during the construction of Palazzo Barberini alle Quattro Fontane (iter 3), projected by Maderno but entirely carried out, after the designer's death, under Bernini's direction with Borromini's technical collaboration. It wasn't an occasional rivalry: temper, culture, even their vision of the world, were, in the two great artists, profoundly different: as different was their technical expertise: incomparable in Bernini's brilliance in conceiving ideas, and exceptionally secure and profound in Borromini. A very original architectonic vision, already mature and singularly coherent also in resorting to bold construction devices was revealed by Borromini ever since the very first job entrusted to him in 1634, that is the rebuilding of the Convent of the Trinitarian with the church of San Carlo di Borromeo alle Quattro Fontane (iter 3); the convent and the church were completed in 1635, while the inside of the church would not be finished but four years later; the convent's façade (1660-65) and the church's prospect (1665-67) will be the last works of the Maestro. Adopting in the church's plant the elliptical shape and aligning the entrance and the high altar on the main axis, Borromini compressed the inner space to the winding line of the perimeter walls, rendered even more animated by the employment of alveolar columns and niches; from the space thus concluded such a strength seems to come forth that it's imparted to the overhanging elements, all the way up to the cupola's summit ended by the small lantern. The Convent of the Filippini was inspired by analog stylistic criteria, begun in 1637, at the same time of Palazzo Spada's perspective gallery and of Palazzo Falconieri's enlargement.

The artist's intolerance for classical regularity finds full confirmation in the façade of the Filippini's oratory, whose architectonically dominating motif is given by the contraposition of recesses and curvilinear overhangs and by the animated and broken rhythm of the tympanums and the cornices. With the death of Urbano VIII and the accession of Innocenzo X to the pontifical throne (1644-55), Bernini's fortune underwent a sudden eclipse and Borromini stepped to the first place among the architects working in Rome . This is the period of the most intense activity: the following works, among others, are of this time: the completion of the church of S. Ivo alla Sapienza, begun in 1642, and the restoration of S. Giovanni in Laterano (iter 4), rapidly led to an end between 1647 and 1649. In S. Ivo, Borromini performed his boldest and most rigorous work; inserted in the courtyard of the Palazzo della Sapienza, built by Giacomo della Porta, the church's façade in its inferior order seems to want to uniform itself to the simple and severe lines of the preexistent building, only to rise up with a outburst of all its framework in a concave star shaped attic, lightened by four perforated openings, atop of which stands the agile spiral lantern, in the likes of a blinking flame in the atmosphere; the same plant, in the shape of an irregular hexagon with niches shaped as semi-circles or as triangles rounded at their vertexes, seems to echo in stylized fashion the heraldic emblem of the Barberini: a further whimsical witness to Borromini 's fantastic liberty and open-minded invention. In 1653 he undertook the direction of the works for the church of S. Agnese in Piazza Navona (iter 6), already begun by Girolamo and Carlo Rainaldi, but he remained on this directing assignment only until 1657 when, after the death of Innocenzo X, the trends contrary to Borromini got the upper hand. Although already begun by the Rainaldi, S. Agnese's façade reassumes the fundamental themes of Borromini's architecture because of the concave course impressed on it by the maestro with the intention of fitting the church in the elliptical course of the piazza, according to the principle of the building's setting in the surrounding space, typical of the baroque art. With equally inventive genius, that would seem to have been stimulated by certain Indian or far-east architectonic forms, Borromini conceived the apse and the campanile of S. Andrea delle Fratte, concluded, on top of the bell-tower's cell, by a large vase with handles that rests on a plinth of caryatids and torches. Among the latter works are the Collegio di Propaganda Fide, begun in 1652 but ended only in '66, and the prospect of the church of S. Carlo alle Quattro Fontane; this, in the easy unfastening of the curvilinear elements underlined by the cornices jutting out with a strong relief, verifies precisely to the conception of the inside; thus the last work of the maestro, tying itself back to his first one, configures as a sort of exasperated synthesis of the stylistic and ornamental themes to which Borromini had remained faithful to all of his life. Although it has long been judged as an extreme aberration of both style and technique, Borromini 's architecture finds its full historical justification in the wider circle of the baroque figurative culture and its inner contradictions.

At the base of Borromini 's art, so tormented and dramatic in the contraction of the constructive space and in the nervous tension of the ornamental elements, there were the same moral and religious ideals that had urged Caravaggio to a profound renewal of the very conception of art. In a way both maestros resent, albeit indirectly, the religious crisis opened by the Reformation and reflect therefore the anxiousness of a spirituality that wants to break loose and express from matter, without any intellectual mediation. The classical restoration carried out by Bernini, albeit in the ambit of the seventeenth century's culture, mirrored instead the ideals of the Catholic Church triumphant with the Counterreformation and thus induced by its very universality to place the Renaissance's intellectualism back to its ancient value. The profound contrast that divided Borromini from Bernini, as already pointed out, cannot be therefore commeasured to a single episode of professional rivalry or to a mutual misunderstanding: it was about two irreconcilable mentalities, necessarily carried by their very own greatness to interpret in a different way the spirituality of the time in which they were called to work: a classically universal Bernini; and Borromini , full of outbursts, of contradictions and of tormented religiousness.

And as his art, restless and anxious, was the maestro's life, his death, dramatic; severely ill, in a rage fit provoked by insomnia, he smote himself with his sword; he died the following day, repented of his deed and – according to his wish – he was buried next to Maderno.