Behind the apses of the Frari, in what looks like a theatre backdrop, opens one of the most scenic campi of Venice: on one side the mighty bare-brick Gothic apses of the basilica, on the other the white masses of the church and the Scuola Grande di San Rocco - the confraternity that gathered the relics of the saint, protector of plague victims, and entrusted Tintoretto with the most famous cycle of paintings in the city.