The term Baroque describes a complex idiom, originating in Rome, embracing painting, and sculpture as well as architecture.

Image source: https://search.creativecommons.org/photos/c2c8e79b-3432-4cd9-a3c8-eaf3e5b505df by vharjadi
When and why the Roman Baroque was born
Baroque architecture originated in the Counter-Reformation when the Catholic Church launched an emotional appeal to the faithful using art and architecture. In the 17th century, Rome became a statement of Catholic majesty, and triumph was expressed through the arts. Baroque architects, artists, and urban planners were used to give power to the ecclesiastical traditions of the city. Rome became the capital of the European art world.

Image source: https://search.creativecommons.org/photos/a823daf7-8dba-4ef8-8d86-defff2085f42 by rjhuttondfw
The most important baroque artists
The architecture of the Roman Baroque can be considered as attributable to the papal reigns of Urban VIII, Innocent X, and Alexander VII. The three main architects of this period were the sculptor Gian Lorenzo Bernini, Francesco Borromini,and the painter Pietro da Cortona. Each of them developed his expression in architecture. Ceilings and vaults of palaces and churches were a communication medium to fulfill propagandistic goals through different ways of expression.
- Baroque painting: illustrated key elements of Catholic dogma;
- Baroque sculpture: was marked by a similar sense of dynamic movement;
- Baroque architecture: was designed to be spectacular;

Image source: https://search.creativecommons.org/photos/2d2fe455-275a-4d5a-bba9-6c125705801e by Fagerjord
Gian Lorenzo Bernini
Gian Lorenzo Bernini dominated Roman art in the 17th century. Under Pope Urban VIII, Bernini gained productivity and development. He was commissioned to build a symbolic structure over the grave of St. Peter in St. Peter’s Basilica in Rome. The immense gilt-bronze baldachin executed between represents the first truly Roman Baroque monument. The baldachin is perfectly proportioned, and by looking at it one can realize that it is as tall as a four-story building. The moving upward to the crown, its dark colors along with burning gold, gives it the resemblance of a living organism. It is an unprecedented fusion of sculpture and architecture.

Image source: https://search.creativecommons.org/photos/ec54a0c1-a3a7-4c40-8777-f9fd3ba2a768 by Gary Lee Todd, Ph.D.
Francesco Borromini
Borromini worked with Bernini to realize Barberini palace and the Baldachin of Saint Peter. Later on, he had an independent commission, for the design of the church of San Carlo alle Quattro Fontane. The building is considered a masterpiece of Roman Baroque architecture. For the facade, Borromini uses two orders: one upper and one lower featuring: a succession of concave surfaces and, on the top, three concave parts and a newsstand convex. The facade was finished with an oval medallion concave surface giving a sense of dynamism.

Image source: https://search.creativecommons.org/photos/cca96206-6499-419e-8d70-96e7d22e617d by Carlo Raso
Borromini also worked on the construction of S. Ivo alla Sapienza. Inside, the ship has a new centralized plan. It is circled with the alternation of concave and convex-ending cornices, leading to a dome decorated with linear arrays of stars and cherubs. The plant forms a six-pointed star. Sant’Ivo alla Sapienza fused excesses from Baroque and some forms of rationality in an innovative concept.

Image source: https://en.wikipedia.org/wiki/Sant%27Ivo_alla_Sapienza#/media/File:SantIvo_Geometry.svg
Info source:
https://www.britannica.com/biography/Gian-Lorenzo-Bernini https://en.wikipedia.org/wiki/Francesco_Borromini http://www.newworldencyclopedia.org/entry/Francesco_Borromini