Great works: Annunciation (1438-45), Fra Angelico

Some great paintings are inexhaustible wells, forever self-replenishing. Such a one is Fra Angelico's frescoed representation of the Annunciation at the monastery of San Marco in the north of Florence. It is a painting of that key moment in the Christian story when the angel Gabriel appears to Mary, and announces that she will give birth to a son by miraculous means. The story, though central to the Christian story, appears in only one of the Gospels, St Luke's. The fresco can still be seen on the first floor of the monastery, at the top of the staircase, where Fra Angelico painted it. It is the first image that you see as you ascend the stairs to the dormitory level, and its position is perfectly calculated to make an overwhelming emotional impact upon the visitor. Other works by Fra Angelico and his followers, one small image in each, can be seen in the tiny monk's cells on the same floor.

The subject was an immensely popular one, painted over and over again during the Renaissance. Some of its greatest interpretations were dramatic – if not histrionic - in the extreme. Lorenzo Lotto's idiosyncratic Venetian version of the same subject, painted about a decade before this one, sees Mary turned away, in fear and apprehension, from the angel Gabriel, who has just appeared in her bedroom, with his crimped, golden hair streaming. It is almost as if she wants to leap out of the picture frame. God is at the window too, pillowed on a cloud, pointing a stern finger at her, unequivocally. She is the chosen one. There is no going back. A small cat at her back does a half leap from the floor in sympathy. The room is cluttered with objects, some of great symbolic signifance.

There are several celebrated paintings by Fra Angelico of the same scene. One of the most awe-inspiring and elaborately sacramental is a panel painting dating from 1432-4 that can be seen at the Museo Diocesano in Cortona. The loggia in which the confrontation takes place looks opulent and fanfarishly stagey in the extreme. Mary sits on a seat covered with a precious fabric. The angel is in brilliant red, with fussy gold embroidery. The fluted columns shine as if reflecting back at us the glory of everything that we are witnessing. In the lower part of the painting, along the bottom of the altarpiece, a long panel tells the story of Mary's life in a frieze of familiar scenes. Mary, prayer book in her lap, listens, rapt, as the angel, both long index fingers pointing, one towards Mary and the other towards God, whose image is represented in the spandrel of the arch above him, explains the overwhelming significance of his visit. You can almost overhear him saying the last words reported by St Luke in the first chapter of his Gospel: "For with God nothing will be impossible."

The scene that Fra Angelico paints on the wall of the monastery just a few years later is dramatically different in mood. In spite of the fact that the scene also takes part in a loggia, the painting is plainer, and altogether more austere and more intimate in mood. These two beings, one human, the other angelic, seem set apart from the world. We see an open doorway at Mary's back, with a small window of the kind that you can still see in the monks' cells in this bedroom. There are spandrels – as in the painting at Cortona – but this time they are empty. Something important is happening, but the angel looks modest and confiding, as if he is engaging in a private conversation. They incline towards each other as if exchanging confidences. There are no trumpet blasts here, no immediate sense that this angel, in spite of the almost comically colourful flourish of his wings, is the emissary of the Creator; that he has suddenly appeared to the horror, awe and consternation of his human and animal witnesses.

The painting – unlike many of the versions by other painters – also lacks the range of symbolic objects that would have reminded onlookers of Mary's chastity: lilies, chasuble, the carafe, the washbasin. Instead, we have a plain wooden fence marking the boundary of a garden in which small spring flowers seem to be growing. Behind that fence Tuscan cypresses are flourishing. There is no holy book on Mary's lap. Instead, she and the angel have their arms folded modestly, one mirroring the other, over their chests in the sign of the cross. Mary sits on a plain-looking wooden stool – it looks more like a milking stool than the kind of splendid object that the mother of the saviour of the world might be expected to occupy. There is a strange stillness about the scene. They look into each other's eyes. They do not seem about to speak. There is nothing more than that. Yet that seems to be sufficient. Mary does not seem to be troubled. If anything, she looks serenely accepting. The colour of their clothing – the extremely delicate pale pink of the angel's robe matches the garment on Mary's upper half – once again lacks the kind of fanfare that give to so many religious paintings of these times their atmosphere of almost otherworldly opulence.

The figures are painted shallowly, harking back to pre-Renaissance painters. This lack of depth contributes to the simplicity of the scene. The whole scene is a masterpiece of quiet understatement.

ABOUT THE ARTIST

Fra Angelico (c.1387-1455) is most celebrated for his series of fresco paintings at the San Marco Monastery in Florence. A brilliant colourist he is a painter who stands on the very cusp of modernity. His painting harks back to Giotto, and his best known pupil was Benozzo Gozzoli.