Borromini, Francesco (fränchāˈskō bōr-rōmēˈnē) [key], 1599–1677, major Italian baroque architect. His first independent commission (begun 1634) was San Carlo alle Quattro Fontane, Rome, one of the masterpieces of the Roman baroque. The church is noted for its undulating rhythm of architectural elements within a basically geometric plan. In 1642 he began the designs for Sant' Ivo della Sapienza, Rome, a dynamic hexagonal structure. He was also entrusted with the reconstruction of St. John the Lateran, as well as the completion of Sant' Agnese in the Piazza Navona and Sant' Andrea della Fratte. Borromini's innovations in palace as well as church design had a tremendous influence in Italy and northern Europe.
See studies by A. Blunt (1979) and Connors (1980).