Body of work

Art - Richard Cork is astonished by the sculptural solidity of Michelangelo's drawings

Towards the end of his long and restlessly energetic life, Michelangelo consigned an enormous number of his own drawings to the flames. The octogenarian artist must have decided that these images, never exhibited and mostly drawn in preparation for projects as ambitious as the Sistine Chapel, were simply not worth keeping. But the British Museum's unmissable show of his surviving drawings proves just how wrong-headed this bonfire was.

Michelangelo's graphic work offers an astonishing wealth of insights into his achievements. Gazing up at the Sistine ceiling with crowds of noisy tourists, we often feel too far removed from the frescoes themselves. Here, by contrast, the artist allows us to look over his shoulder as he draws models posing for Adam, God and the other heroic figures who charge the Vatican chapel with their twisting, hurtling and gesticulating dynamism.

The young Michelangelo could not wait to acquire this prowess. His father, a frustrated and impoverished civil servant, frowned on his son's choice of career: he believed that artists suffered from an irredeemably low social status. But the 12-year-old boy proved so precocious that he was accepted as an apprentice by one of the leading painters in Florence, Domenico Ghirlandaio. He developed so swiftly that his early drawings already possess a formidable amount of sculptural solidity. It is easy to imagine the ink study of An old man wearing a hat (philoso-pher) as a monumental carved statue, and the pen-strokes attack the paper with the decisive strength of a chisel.

Who taught this prodigy how to carve? We do not know, but he was able to produce the superbly crafted and elegiac Pietà, now at St Peter's, while still in his early twenties. No drawings survive either for the Pietà or the colossal David, which earned him such a legendary reputation. He must have produced countless studies for both these carvings, but they were probably destroyed in his catastrophic fire, so the 95 drawings assembled at the British Museum are miraculous survivors. Some of the most arresting of these images were made for his commissioned mural called The Battle of Cascina. Along with Leonardo da Vinci's Battle of Anghiari, it was designed for the walls of the Great Council Chamber in Florence's Palazzo Vecchio, as a celebration of Florentine military victories. But Michelangelo got no further than drawing a lost full-scale cartoon for the central section, and these preliminary drawings now provide the only reliable record of his intentions.

The Battle of Cascina would have been a tour de force. Having taken off their armour to bathe in the River Arno, the Florentine soldiers hear their captain shout that the enemy is advancing fast. All the muscular bodies tilt, reel and arch in reaction to the news. Two black chalk studies catch the flexed power and urgency of their limbs, but the most impressive is an ink-wash drawing of a seated man swivelling around from the river bank to stare at the commotion behind him. Michelangelo seizes on the sense of emergency with incisive flair; he also invests this twisting nude with the palpable presence of a figure cast in gleaming bronze.

By this time, Michelangelo's knowledge of human anatomy had become formidable. Like Leonardo, he reportedly made dissections of dead bodies and, according to his 16th-century biographer Ascanio Condivi, intended to publish these ana-tomical studies. Although the plan was never realised, we can see how his probing researches bore fruit in the magnificent studies for the Sistine Chapel. Pope Julius II granted him the commission in 1508, and he completed the 40-metre-long ceiling four years later. It was a truly epic enterprise, painted largely by Michelangelo alone after he sacked all his assistants. And the drawings vividly disclose how he measured up to this immense challenge.

Eight leaves from a pocket sketchbook, loaned by the Ashmolean Museum in Oxford, reveal his initial thoughts for several of the figures. Executed rapidly in deft strokes of black chalk, they are the epitome of linear economy and are confined largely to essential contours alone. However, the red chalk drawings of single figures, many lent by the Teylers Museum in Haarlem, are fleshed out with overwhelming mastery. And Michelangelo grows even more imperious when he tackles the reclining figure of Adam. Half languorously reclining and half reacting to the advent of God, this majestic being is already defined with certitude. In reality, Adam's upper body would have suffered from painful dislocation if he had adopted this pose, but Michelangelo makes it appear inevitable.

The Sistine drawings mark a turning point in Michelangelo's vision of humanity. From then on, the bodies he delineates begin to lose their corporeal substance. Almost a decade later, making studies for the marble figure of Day for the Medici family chapel of San Lorenzo, he wields his black chalk in a more vaporous way. The recumbent body is even more massive than Adam, and yet it seems on the point of melting into the paper.

By now, Michelangelo was nearly 50 and growing ever more conscious of mortality. When he urged one of his pupils to "draw, Antonio, draw and don't waste time", he was probably giving vent to his own increasing awareness of life's brevity. Working on The Last Judgement during the late 1530s, as the last phase of his fresco sequence in the Sistine Chapel, he still drew A male nude seen from behind with complete anatomical conviction. At the same time, however, this bulky figure lacks the solidity of Adam. Michelangelo handles the black chalk as if he sees the man as half titan, half ghost.

The dissolution reaches its most moving form in the final sequence of Crucifixion drawings. Produced during the last dec-ade of the artist's life, when he was over 80, they are preoccupied with the shedding of bodily substance. In the most vestigial of these images, he uses lead white to turn the chalk figures into spectres. While Christ's once-heroic body sags and fades on the merciless cross, the Virgin presses anxiously against his bare leg as if to prevent him from leaving her, but she has already been robbed of all flesh-and-blood vitality. Blanched and hovering on the edge of invisibility, she conveys Michelangelo's own realisation that even the most resplendent bodies fade, eventually, from sight.

"Michelangelo Drawings: closer to the master" is at the British Museum, London WC1 (020 7323 8181) until 25 June. www.thebritishmuseum.ac.uk