entrance to Hell in medieval Christian iconography
Hellmouth
The Hellmouth is the entrance to Hell, depicted as the gaping jaws of a enormous monster. It first appeared in Anglo-Saxon art and spread across Europe, where it was a common feature of Last Judgment scenes and of the Harrowing of Hell.
The myth
In medieval art, the damned enter through these jaws, often naked and sometimes wearing signs of their rank, such as the papal tiara or a king's crown. In the Anglo-Saxon Vercelli Homilies, Satan is likened to a dragon swallowing the damned, and an Old English poem in the Exeter Book compares the mouth of Hell to a whale's mouth. Meyer Schapiro suggested that the motif may have grown out of the Norse myth of the Crack of Doom, with the jaws of the wolf Fenrir, but this is a modern hypothesis rather than a certain fact.
Legacy
It appears in El Greco's paintings of about 1578, in polemical prints after the Protestant Reformation and in political cartoons showing Napoleon leading his troops into one. Albrecht Dürer included it in his woodcut The Four Horsemen of the Apocalypse, where it swallows a bishop.
Ancient sources: The Anglo-Saxon Vercelli Homilies and the poem The Whale from the Exeter Book, which compares the mouth of Hell to a whale's mouth.