The basilica was built by emperor Costantinus; the same seems to have given it to the Pope who became the official owner; at the time, it was associated with a building, the Patriarchio.
It was used as a summer residence by Popes.

In 1586, it was rebuilt by Domenico Fontana but before that time it underwent a relevant number of restaurations, modifications, etc...
Of the medieval church, the pavement was made by the notorious "Cosmati", a family of artisans/artists who are renowed for this kind of production.