How did Francesco Borromini help shape the Baroque style of architecture in Rome?

Francesco Borromini was a chief formulator of the Baroque style, distinguishing himself from contemporaries like Gian Lorenzo Bernini through his unique approach to design and geometry.12

Architectural Innovations

Borromini’s influence on the Baroque style was defined by several key contributions:

• Geometric Foundations: Unlike architects who derived proportions from the human body, Borromini based his designs on complex geometric configurations—such as irregular ovals, octagons, and hexagons—often utilizing modular subunits.123
• Fluidity and Movement: His works are characterized by active, undulating concave and convex surfaces that create a sense of dynamic movement. A prime example is San Carlo alle Quattro Fontane, where the undulating facade and irregular floor plan were highly influential and subsequently adopted by other architects.24
• Structural Virtuosity: Drawing on his background in the artisan traditions of Lombardy, he utilized structural ribwork and innovative brickwork to achieve complex forms, such as his inventive domes and vaults.23
• Spatial and Light Effects: He employed calculated lighting to create bold, illusionistic effects, often making architectural elements appear to float or expand, as seen in the interior of San Carlo.3

Borromini’s bold, vigorous designs, particularly his palace facades, served as a major source of inspiration for the development of the Rococo style in the 18th century.2