Located under the church and entered through the spacious courtyard that opens onto Via Sant’Agata, the ancient crypt of the Augustinians has practically nothing left of its original appearance, due to the transformations that have taken place over the centuries. Built at the time of the thirteenth and fifteenth-century expansions of the church above it, the crypt was officiated, starting in 1423-1424, by one of the private association of laymen with a religious purpose which grew up in the Middle Ages to aid the sick and needy, known as Lay Companies or Confraternities. We know nothing about the company which officiated in the Sant’Agostino crypt except that its members were presumably drawn from the nobility. This company, named for the Holy Cross (Santa Croce), probably had among its members the young Fabio Chigi, who went on to become pope, taking the name of Alexander VII. In 1500 the members of the confraternity decided to have the interior frescoed by some of the leading artists of that time. The scenes from the Passion of Christ, painted by the Lombard artist Giovanni Antonio Bazzi, known as Sodoma, and another fresco series depicting episodes from the life of Christ date to that period.

Suppressed as a result of the reforms enacted by Grand Duke Leopold in 1785, the crypt was abandoned and used for a long time as a granary and storehouse. Many of the paintings in it . . .