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.
Cristoforo di Geremia
One of the most prominent commissions that brought Cristoforo fame was the restoration of the equestrian statue of Marcus Aurelius in 1468. In 1469, he was commissioned to make medals for the restoration of the Palazzo Venezia. The pope strategically employed Cristoforo to use the antique concepts he was known for, but had him also cater to Pope Paul II's liking. Under the papacy, Cristoforo made a plethora of medals for Pope Paul II. Pope Paul II often buried medals in the foundations of buildings he was restoring. Many of these medals have since been recovered and attributed to Cristoforo di Geremia, despite the lack of a signature.