Santa Maria del Popolo
The architect or architects of this innovative project remain unknown due to a lack of contemporary sources. Giorgio Vasari in his "Lives" attributed all the important papal projects in Rome during Sixtus IV to a Florentine, Baccio Pontelli including the basilica and monastery of Santa Maria del Popolo. Modern researchers deemed this claim highly dubious and proposed other names among them Andrea Bregno, a Lombard sculptor and architect whose workshop certainly received important commissions in the basilica. The fundamental differences between the façade and the interior suggest that maybe more than one architect was working on the building.
Montemirabile Chapel (Santa Maria del Popolo)
The chapel is named after Giovanni Montemirabile (an italianized name for Jean de Montmirail), the bishop of Vaison and confidant of Pope Sixtus IV, who was buried here after the chapel had been built in the 1470s. This was the first of the original four identitcal chapels on the left side and it was dedicated to St. John the Baptist. The chapel was transformed into the baptistery of the basilica in 1561. After 1568 a Renaissance funeral monument was built for Cardinal Francesco Abbondio Castiglioni by the right side wall. The monumental Renaissance wall tomb of Cardinal Antoniotto Pallavicini was transferred to the chapel in the second quarter of the 17th century, its bulk partially hiding from view or replacing the original painted decoration of the left wall. In 1657 fragments of a demolished quattrocento monument from the choir were reassembled in the chapel in the form of two aediculae by Cardinal Flavio Chigi, the nephew of Pope Alexander VII, who was Cardinal-Priest of the basilica at the time.