Carlo Crivelli, 'Predella of La Madonna della Rondine', after 1490

This predella comes from an altarpiece that Crivelli painted for the Ottoni family chapel in the Franciscan church at Matelica. Its scenes reflect the patrons' interests: one was a churchman, the other a soldier.

On our left is Saint Catherine of Alexandria, one hand resting on her main attribute, a spiked wheel. To show off his skill at foreshortening, Crivelli has rotated this so that we see it side on, its spokes retreating at a sharp angle. According to her legend, Catherine was a Christian princess whose arguments defeated those of the Roman philosophers brought to debate with her. When she then refused to marry the Roman emperor, he had her tortured on a wheel. She stands for theological learning and the defence of the Church by intellectual argument. But this is no unwordly academic: from her hair, crown and pearl circlet – pearls were symbols of chastity – to her golden brocade over-dress, its sleeves slashed to show her linen shirt, she is dressed in the height of late fifteenth-century Italian fashion. A translucent veil floats behind her, and elongated features and fingers emphasise her elegance.

At the opposite end, Saint George raises his sword to slay an incongruously small dragon. His stallion rears in alarm, twisting its head up and away from the dragon. In the background the princess kneels on a rocky outcrop, while her father and his subjects watch from the safety of a walled city. This saintly warrior exemplifies the knightly ethic of the Ottoni family (Ranuzio Ottoni was to die fighting against the French in 1510).

The central scenes tell the stories of the figures represented in the main panel of the altarpiece. In the middle is the Nativity. Finding no room at Bethlehem, the holy family have set up camp in the best place available. On the shelves behind them we see pots and pans, a book, a straw-bound carafe and a flask of wine. Through the arch to right shepherds gaze up in amazement at the choir of angels, while their dog sleeps oblivious. To the left other travellers make their way through tidy gardens to the gates of Bethlehem.

To the left, Saint Jerome, his cardinal’s hat hung on a convenient tree, kneels before a crucifix, grasping a stone with which to beat his chest. Before translating the Bible, Jerome was thought to have spent time in the desert repenting his sins. His lion lies like a large dog beside him and around him are desert animals: a snake, a vulture and a dragon, perhaps symbolising temptation overcome and linking him with Saint George. In his roughly built hut is a shelf of domestic odds and ends, a desk loaded with books – the saint took his library with him – and a pen case hanging from the wall.

To the right, Saint Sebastian is martyred. The saint, clearly the same young man shown in the altarpiece’s main panel –- notice his upturned fringe and flying golden locks – has been stripped of his finery and strung up in the bare branches of a tree. Through the arch behind him we see figures strolling in a courtyard, either unmoved or unaware of the martyrdom taking place so close by.

With the exception of Saint Catherine, the soft tones and barren landscapes of the predella scenes contrast vividly with the glowing splendour of the main panel.