Begun by F. Ponzio and O. Mascherino. The Quirinal is the official residence of the President of the Italian Republic upon the Quirinal Hill, the tallest of the seven hills of Rome. The Palazzo del Quirinale was begun in the late 16th century and commissioned by Pope Gregory XIII as a Papal residence. It later became a royal palace. Various architects worked on the project, including Carlo Maderno who designed the chapel, Bernini who designed a wing, and Pietro da Cortona who decorated parts of the interior.