The church was designed by Maestro Jacopo Tedesco on two levels, each of which is consecrated as a church. They are known as the "Basilica superiore" (The Upper Basilica), generally called "The Upper Church" and the "Basilica inferiore" (The Lower Basilica), generally called "The Lower Church". The Lower Church was structurally a large crypt supporting the upper one. In the 19th century a lower crypt was constructed beneath the basilica. Architecturally, the exterior of the basilica appears united with the Friary of St. Francis, since the lofty arcades of the latter support and buttress the church in its apparently precarious position on the hillside.