These six plaster casts are test models made by the Florentine sculptors Emilio Gallori and Cesare Zocchi around 1880, for the eight marble reliefs that decorate the vertical embrasures of the south door of the Cathedral facade.

The six winged figures are placed within hexagonal frames, inspired by those of the reliefs of Giotto's Bell Tower, and are depicted with eloquent poses and expressions of fear and anguish. They are the angels allied to Lucifer, meaning the demons, who according to Christian faith were defeated by God and the heavenly armies of St. Michael the Archangel and thrown into Hell, at the beginning of time. In the portal they are opposed to the angels and archangels who decorate the opening of the tympanum.

These decorations are part of the extensive iconographic program of the facade, designed by the architect De Fabris, responsible for the construction of the new architectural front, together with the philosopher Augusto Conti.