The tomb of the first Pope, St. Peter, was at first a modest burial site, on which a small funerary aedicule was built around one hundred years after the Apostle's martyrdom.

The presbyter Gaius commemorated the site at the end of the second century, according to the historian Eusebius of Caesarea (Ecclesiastical History, 2, 25, 6-7).

Often referred to as the "Trophy of Gaius," the aedicule pointed early Christians to the tomb of Peter, which was the destination of devout pilgrimages, even before the time of the Emperor Constantine.