Dolphins were a common sight in Italian coastal waters and would have been classified as fish (rather than mammals) in Cassiano’s time. This drawing was seen by the English naturalist Philip Skippon on a visit to the Dal Pozzo residence in 1662: ‘a dolphin brought to the fishmarket in Rome, having one fin on the middle of the back, a pair of fins under the gills, a longish snout, wide mouth, a forked tail, and well armed with sharp teeth’.