Italian Architect ( Milan around 1560 – Rome 1613). It seems that he immigrated to Rome while still very young, but no work of his carried out before he was forty is known in this city or in any other place. Almost certainly he was formed in the circle of the Flemish and Lombard artists living in Rome , which gave a notable impulse to the Counter-Reformation architecture initiated by D. Fontana. Still in classical fashion in the well-balanced façade of Palazzo Sciarra, Ponzio later adhered strictly to Fontana 's style, adding to it original decorative researches that prelude to the baroque. Between 1605 and 1611, charged by Paolo V, he built the Cappella Paolina in Santa Maria Maggiore ( iter 3 ) that, erected in front of the Sistine Chapel built in the same basilica by Fontana , faithfully reproduces its architectonic lines, yet distinguishing itself from the former by the unity of the rich decoration. Among other works built by him in Rome these are to be remembered: the north side of the courtyard, the two-fold stair steps and the Sala Regia in the Quirinal, the prolongation of Palazzo Borghese towards Via Ripetta, Palazzo Rospigliosi, the New Sacristy of Santa Maria Maggiore, ecc.