Foundation medal for the façade of the new Saint Peter's Basilica. The reverse illustrates the planned design for the façade by the architect Carlo Maderno. The exergual inscription on the reverse is taken from Matthew 16:18; Et ego dico tibi: Tu es Petrus, et super hanc petram aedificabo Ecclesiam meam; et portae inferi non praevalebunt adversum eam (And I say to thee: That thou art Peter; and upon this rock I will build my church, and the gates of hell shall not prevail against it).

One of the first tasks Paul V undertook was to complete the new Saint Peter's Basilica, which had been under construction for over 100 years, the first foundation stone being laid in 1506. Carlo Maderno was appointed as the architect charged with completing the structure. The two main tasks included designnig an extension the nave of the church (forming a Latin cross instead of the Greek cross from Michelangelo's plans) and designing the façade for the grand structure. Unfortunately, the extension of the nave destroyed the view of the front of the church. Though the view on the medal might be correct from a purely orthographic projection, the actual view from in front of the basilica finds the two small side domes completely obscured and the large central dome nearly so. On February 10, 1608, the first stone of the façade was blessed by the pope and ceremoniously laid into place.