Hellmouth is the entrance to Hell envisaged as the gaping mouth of a huge monster, an image which first appears in Anglo-Saxon art, and then spread all over Europe, remaining very common in depictions of the Last Judgment and Harrowing of Hell until the end of the Middle Ages, and still sometimes used during the Renaissance and after. It enjoyed something of a revival in polemical popular prints after the Protestant Reformation, when figures from the opposite side would be shown disappearing into the mouth. A notable late appearance is in the two versions of a painting by El Greco of about 1578.Political cartoons still showed Napoleon leading his troops into one.
Medieval theatre often had a hellmouth prop or mechanical device which was used to attempt to scare the audience by vividly dramatizing an entrance to Hell. These seem often to have featured a battlemented castle entrance, in painting usually associated with Heaven.
The oldest example of an animal Hellmouth known to Meyer Schapiro was an ivory carving of c. 800 in the Victoria and Albert Museum, and he says most examples before the 12th century are English. Many show the Harrowing of Hell, which appealed to Anglo-Saxon taste, as a successful military raid by Christ. Schapiro speculates that the image may have drawn from the pagan myth of the Crack of Doom, with the mouth that of the wolf-monster Fenrir, slain by Vidar, who is used as a symbol of Christ on the Gosforth Cross and other pieces of Anglo-Scandinavian art. In the assimilation of Christianised Viking populations in northern England, the Church was surprisingly ready to allow the association of pagan mythological images with Christian ones, in hogback grave markers for example.