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.
Santa Maria del Popolo
The organ in the right transept was originally built in 1499–1500 by Stefano Pavoni, "magister organorum" from Salerno; its case was decorated with the coat of arms of Pope Alexander VI who probably contributed to the expenses. During the Berninian reconstruction of the basilica this instrument was rebuilt by organ master Giuseppe Testa who also created a new organ for the left transept. Both organs has long since disappeared with only the organ-case in the right transept remaining in place. For the left cantoria a modern organ was made by Carlo Vegezzi Bossi which was inaugurated on 23 May 1906.