"Church of San Carlo alle Quattro Fontane"

The building site was challenging, as the church was located at the corner of an intersection, and had an adjoining cloister on one side that the architect also designed. Cardinal Francesco Barberini commissioned the church in 1634 and it was the architect's first major commission, though due to various financial difficulties and changes of patronage, it was not completed until after the architect's death. As art critic Olivier Bernier wrote, "based... on geometry... in the handling of form, volume and light... his buildings, although they unmistakably belong to their century, often have a startlingly modern look. Constantly playing with rounded forms - concave and convex cylinders are extensively used - Borromini gives his facades amazing animation without ever relying on mere decoration."