The Pauline Chapel is the heart of the complex building plan of Saint Mary Major, implemented by Paul V.
The entire chapel is decorated with precious coloured marble, all the way up to the area of the cupola. Its elegance increases as one approaches the tabernacle-reliquary of the Salus Populi Romani. Designed by Girolamo Rainaldi and made by Pompeo Targone, it is composed of four columns in jasper from Barga. It is covered in a uniform layer of lapis lazuli that evokes a cloudy sky and a heavenly gate. The frescoes (1610-12) were painted under the supervision of Giuseppe Cesare, known as Cavalier d’Arpino, who directed a group of painters, including artists of the calibre of Giovanni Baglione, Lodovico Cigoli and Guido Reni.
The cupola, painted by Lodovico Cigoli, depicts the Mother of God being welcomed into heavenly glory. Mary rests on a realistic reproduction of the moon that corresponds to the astronomical observations Galileo Galilei published in his 1610 treatise Sidereus Nuncius.