Nowadays the Maesta is kept behind glass in in Siena’s Cathedral Museum, where it has become a cult object for tourists and parties of schoolchildren. Its front and back sections were separated from one another during the eighteenth century, and some of its panels were destroyed or sold (a particularly beautiful fragment of the back predella is in the National Gallery). But even in its somewhat battered modern state, once seen it is not quickly forgotten. Duccio: The Maesta, a new and exhaustively illustrated picture book from Thames and Hudson, makes it possible to revisit and reexplore the memory of this extraordinary object. It is a higher form of souvenir. There should be more books like it.

The main front panel of Duccio’s  altarpiece shows the Virgin Mary, with the Christ child on her knee, surrounded by an assembly of adoring angels and saints. Devotion to the Madonna is almost as old as Christianity itself, but the cult of Mary had been intensified in Italy during the thirteenth and early fourteenth centuries by the rise of the mendicant orders. Preaching friars such as St Francis of Assisi and St Dominic had galvanised their followers with their renewed emphasis on the pathos and immediacy of the Christian story. Their focus on Christ the babe in arms and Christ the suffering man also brought about a new sympathy for, and identification with, his loving mother. Thus Duccio depicted Mary as a universal mother, her  almond eyes brimming over with compassion. She is a great vessel of sympathy, with enough to go around for everyone.

The heaven which she occupies seems almost woven rather than painted. The artist has conceived her court as a kind of textile emporium, threaded through with alien beauty. Duccio’s sense of design was enriched by a boom in textile imports into Italy in his day. The Sienese imported cloth from the Far and the Near East, from China and the Ottoman Empire. Moorish geometrical patterns could be seen on fabrics imported from Spain, while Chinese patterned silks had been introduced via Venice by traders in the late thirteenth century. These patterns, and new effects, such as damasking and satin weave, were evoked by Duccio both in paint and in skilfully worked gold leaf. The painter’s easy, fruitful amalgamation of decorative influences from the East and from Africa prefigures the orientalism of much later artists, such as Delacroix or Matisse, although the powerful effects which Duccio creates from his mesh of patterning and colour have little if anything in common with those of more modern art. They seem intended to encourage a mystical state of rapture, a kind of hypnosis by buzzing, pulsating design.

There is an oriental quality, too, to some of the sinuous figures which crowd the panel. It is as if Duccio’s attraction to Chinese, Persian and Islamic decorative motifs infused his whole imagination. Yet suspended within this shimmering fabric of an image, with the iconic virgin and child at its centre, the faces of the saints have a powerful actuality.

Duccio painted the back of his altarpiece with many much smaller narrative scenes, depicting scenes from Christ’s Passion with a broad and deep understanding of human character. The pictures that form this chequered history are shot through with brilliant, small flashes of anecdotal realism. The artist paints the apostles asleep in the Garden of Gethsemane as if they were vagrants sleeping rough. He depicts the cruelty of Christ’s tormentors with the conviction of a man who has himself witnessed crowds turning ugly. He paints the turn of a mood too, catching Peter’s complacency as it gives way to shock in the house of the high priest. Warming his feet by the fire, we see him suddenly accosted by the priest’s maidservant, who elicits the first of his blurted denials of Christ. The character of St Peter as it comes across from the gospels - impetuous but engaging, full of frailty but ultimately a rock - has never been captured more convincingly in art. Paintings such as Duccio’s, rendering the stories of the Bible for those who might not be able to read, were truly “books for the unlearned”. They were also the advance guard for the vivid, vernacular, storytelling literature of writers such as Boccaccio (and Chaucer).

The landscape in which Duccio places his actors is a fluid place. No one ever quite stands firm on its shifting ground. This suits the artist’s interpretation of the character of Christ. He is inherently edgy and uncomfortable and is suited, from the perspective of tragic expression, by a world in which he cannot settle. He is slender and wistful and not terribly authoritative in many of the scenes on the back predella of the Maesta. A saddened victim of atrocities, he never seems at home. As the story of the Passion unfolds, he becomes progressively more alone. In scene after scene, Duccio emphasises his isolation. The artist depicted more events from the Passion than was customary in most painted cycles, taking care, for instance, to depict all three of St Peter’s denials of Christ. This may, in part, be another expression of his preoccupation with pattern, Duccio playing variations on the theme of betrayal. But the design of his work is inseparable from its pathos. By slowing down the narrative of the Passion, by showing us so many of the moments when it might have taken a different turn, Duccio inflicts its grim inevitability on us all the more tellingly.

In the scene of the Crucifixion, the centre and climax of his story, Duccio divides the assembled crowd into a good half and an evil half and here, once again, he seems to adapt his style according to his meaning. The wicked soldiers and jews on the right are depicted in a style that might almost be that of some unusually gifted folk artist; yet on the left a great subtlety of line and delicacy of expression has been reserved for the apostles and Mary. Christ has been painted as if he were a Gothic or Byzantine ivory figurine.

As the religious mystery of the story deepens, and as the pathos of Christ’s death gives way to the solemn mystery of his reincarnation, the artist’s style becomes more fugitive and incorporeal. All that is solid seems on the point of melting into thin air. The figures seem like flames not flesh, emanations of pure spirit. Were they meant to evoke mystical experience, the ecstatic suspension of the body between heaven and earth?

Perhaps the most intriguing reference to Duccio in the Sienese archives records that on 22 December 1302 he was accused of sorcery and “taken before the magistrate for witchcraft in the district of Chamomilla”. The accusation cannot have been taken very seriously. He was fined the risible amount of five soldi and allowed to go on his way. But maybe there was something in it. The Maesta proves that Duccio was a magician, of a kind.