The DIY University: Renaissance Art; Week 4 Day 1

In the small city-republic of Florence, in the years around 1400, a self-consciously new art was created, whose ideals and discoveries were to dominate western European painting until the advent of the modern era, five centuries later. The new art was confident and learned, and it was devoted to the imitation and representation of nature, on the basis of objective analysis. The old Gothic pictorial conventions were sloughed off, and an art linked with life, concerned with the beauty and emotional power of the human figure, replaced the transcendental and symbolic art of the Middle Ages. It was nurtured by a humanist faith in the dignity of man, and it seemed as though, after the darkness of centuries, the true art of antiquity had been reborn.

Its first historian, Giorgio Vasari, used the word rinascita (rebirth), evoking an optimistic and exhilarating newness. Painters emulated the fabled illusionist skills of ancient artists, and painting was once again envisioned as a triumphant progress to an ever more perfect replica of reality.

The absolutely crucial scientific discovery that underpinned Renaissance painting was undoubtedly the Florentine system of single-point perspective which, with the study of naturalistic light, enabled early Renaissance painters to achieve a totally new kind of three-dimensional illusionism and realism. A painting was likened to a view through a window, and Antonello da Messina's small panel St Jerome In His Study (c1475; London, National Gallery) seems to play on the theme of creating a world within worlds. We peer through a painted arch to the lovingly detailed scholar's study, but beyond lie further windows, and beyond them, a glimpse of the riches of the natural world. The clear daylight and the way in which the perspective emphasises the scholar's concentration convey a Renaissance admiration for learning and reason.

Painting's new naturalism was enhanced by a study of anatomy, and a variety of new skills are displayed in Antonio and Piero del Pollaiulo's Renaissance showcase, The Martyrdom of St Sebastian (1475; London, National Gallery). In the foreground an ostentatiously balanced pyramid of athletic executioners demonstrates an exhilarating mastery of the human figure in complex action. The same figure is shown from different viewpoints, draped and nude; a taut and springing line conveys the vivid life of muscle and vein, and follows the play of sharp angles and curves. But beyond, in a panoramic view of the valley of the Arno, Antonio demonstrates other naturalist effects, creating atmospheric space through the soft play of light and shade that gleams on the river and fades on a distant horizon.

To Vasari this naturalism of the 15th century rapidly came to seem a "dry, hard, harsh style", and it was eclipsed by the "inspired grace" and monumentality of the great 16th-century painters, Raphael, Leonardo da Vinci and Michelangelo, who were accorded a quasi-divine stature.

Art now aspired to an ideal beauty, that should surpass nature; 15th- century clarity yielded to the soft shadows of Leonardo, which created a mysterious and poetic vision, and the grandest of Raphael's Madonnas were both visionary and yet warmly human. For Michelangelo, man is raised to heaven by the contemplation of human beauty, and the heroic yet suffering and defiant male nudes of the Sistine ceiling suggest a yearning for a spiritual beauty that transcends reality.

Most Renaissance art was religious, but artists also evoked the lost world of classical antiquity. In Venice, poets and painters recreated the ancient dream of an Arcadian landscape, peopled by gods and shepherds, whose beauties offered refreshment and a natural eroticism. Such a landscape forms the setting for Titian's Bacchus and Ariadne (1520-30; London, National Gallery) in which the sensuous beauty of antique myth is radiantly brought to life. Inspired by Catullus, it shows the discovery of an abandoned Ariadne by the god Bacchus and his frenzied train. At the picture's centre, Bacchus, "seeking thee Ariadne and fired with thy love", leaps from his chariot, creating a sense of sudden revelation, of both the terror and beauty of the pagan world. A powerful nude grapples with snakes, evoking the newly discovered and celebrated classical sculpture, the Laokoon. The picture celebrates love, and glows with the rich beauty of precious pigments, setting the ultramarine expanse of the sky against earthy browns and greens. Titian invested the medium of oil on canvas with new strength, and Venetian colourism was to dominate European art in the following centuries.

In the modern era, the most revered Renaissance artists are perhaps those who used their skills for non-naturalistic ends; Uccello, whose passion for perspective created a highly unreal and fantastic world, and Piero della Francesca, who united an intense naturalism with a poetic response to the abstract beauty of space and form.

Tomorrow: Modern Art