Anonymous: Helmouth, from the Winchester Psalter (c1150)

Inside and outside: that's a basic relationship in pictures. You draw a line around to make an enclosed area. The line is an outline, an edge. It marks the boundary between what's inside this area, and what's outside. It creates a distinct space, a defined entity - which can then be made to stand for some kind of creature or object, a cloud or a hole, whatever. But defining a two-dimensional area, establishing an inside and an outside, is the first step in picture-making. It can be made a source of drama in itself.

In the medieval imagination, the mouth of Hell was often pictured as a real mouth. It was the mouth of a great beast, a sea creature, a whale, Leviathan. Hellmouth is the name of this image, and it appeared in many different forms. It might be constructed as a piece of scenery in a mystery play, or carved in stone on the tympanum of a Romanesque church, or painted on church walls, or in manuscript illuminations.

Several Biblical texts inspired this idea, though there is no unequivocal scriptural authority for it. It manages to combine a number of bad, fearful and hellish things. The creature is monstrous and slimy. Its mouth is a dark and cavernous prison. It is toothed and ever-hungry.

In other ways, too, being in Hell is like being in a mouth. If you're eaten alive, you aren't killed outright, your body is transformed bit by bit into edible matter' like the damned, you are alive and dead together. And, because a mouth can chew on a piece of food or non-food almost indefinitely, chewing is also a good image for the interminable and continuous torments of Hell. The lost are in a state of being eternally eaten alive, munched upon forever.

In pictures, Hellmouth is generally not much more than a mouth, a face without a body, a pair of jaws plus eyes. It typically appears in a Doom, a Last Judgement scene, at the bottom or in the bottom right-hand corner. It is wide-open like a mantrap, a gaping cavity into which the souls of sinners are shown tumbling and being shovelled and prodded by devils.

What makes Hellmouth especially monstrous is that it is not a fully living creature. It's just a detached organ, with a reflex action, a bit of flesh that blindly pursues its bodily function even though separated from an active body. This is a motif familiar from horror films - the severed hand that still grasps, the plucked-out eye that still sees. The huge mouth that munches on automatically is as damned as any of the damned it consumes.

You find a similar notion in Dante's Inferno (though Dante doesn't use the Hellmouth image as such). Satan, lying at the bottom of Hell, is an automaton, a giant animated corpse, whose three mouths perpetually, mechanically, chomp on the bodies of the worst sinners, "like a mill".

With Hellmouth, as with Hell itself, you can see things in alternative ways. You can stress how easy it is to get in - or how hard it is to get out again. One way, Hell is a constant danger, always open. The other way, Hell is a closed trap. The majority of Hellmouth images show an open mouth, with the damned falling in. But, in this picture, a page from the Winchester Psalter, the mouth is closed.

It is not a Last Judgement, with the infernal maw lying on its back, open to all. The mouth is turned sideways, and the stress is on containment. The episode illustrated is from the very end of the history of everything, when the saved and the damned have conclusively been separated, and the angel comes down and puts a padlock on the jaws of Hell. Ici est enferseli angels ki enferme lesportes' here is hell and the angel who closes the gate: so says the little caption along the top of the image in oldish French. It's all over. No one else will ever go to Hell, that's the idea. But of course what the image emphasises is that no one will ever now escape.

The interior of Hellmouth is shown, not as a voluminous cavern, but as a two-dimensional area, a D-shaped enclosure. To be inside the mouth is to be inside this area, and the power of the image lies in that equation. Corralled within are the naked human damned (among them kings, queens, and monks) mixed with horned and hairy demons - a mêlée of figures clearly delineated against a dark ground. They are pressed together within this mouth-area as if they were all lying on the same flat plane, like coins in a "penny falls" slot machine, shoved edge-to-edge, sometimes overlapping. They're ringed in by curving walls of teeth. The experience of being crammed into a mouth is vividly displayed, in cross-section, so to speak.

As often in illuminated manuscripts, the edge of the image itself is made part of the image. The angel who turns the key stands outside the oblong picture, in the blank margin of the page. The padlock more or less coincides with the decorative border. The frame of the image is equated with the outer limits of hell. The angel arrives from another realm.

Within this bolted Hellmouth, the torment and pressure go in two directions. The figures in the mouth are like sardines, cramped and crushed together. But, equally, they're like gob-stoppers. Turn the page round and look at the monstrous scaly beast-face itself, torn apart into its upper and lower halves. Look at the stretch marks round the lips, the boggling eyes. You see a mouth that's stuffed with more things than it can hold, gagging eternally on its unfeasible mouthful. It's hell, being Hell.