Page from a late 13 c. copy of the Decretals of Gregory IX, now in the Biblioteca Medicea Laurenziana, Florence
Fanciful 16th c. fresco depicting Gregory excommunicating Frederick II in the Sala Regia, by Giorgio Vasari. Since few details were provided to the artist, the excommunication scene is given generically. Frederick is shown pointing to a book with the word "Concilium" shown, possibly a reference to the general council that the emperor attempted to call to depose Gregory.