Gentileschi at the National Gallery

Art historians, who love labels, often refer to Orazio Gentileschi as a Caravaggist. Gentileschi, a friendly but not an intimate acquaintance of the more vehement Caravaggio, certainly discovered his true bent in Caravaggio's unheroic style of painting. It was what established him as a master after twenty years of barren endeavour. He adopted Caravaggio's naturalism but not his ferocity, his livid colours, and the swarming shadows so earnestly exploited by Ribera and Caracciolo in Naples, and by Terbrugghen and Honthorst in Utrecht. Orazio's bloodthirsty daughter Artemisia was a more thoroughgoing imitator of Caravaggio than her father ever was.

In his life as in his painting, Gentileschi was a milder Caravaggio, without dire actions and dark extremes. Both were wanderers: Caravaggio in flight from arrest for his many misdeeds, which included defamation brawls and outright manslaughter. He died in outlawry, confused and fever at the age of thirty-six in 1610. Gentileschi remained sedate until, in middle age, an outrage to his family sent him on his travels. He died at the age of seventysix in London after drawing up a reasoned and circumspect will. Having migrated from Pisa to Rome at the age of fifteen, he stayed there for thirtythree years of industrious obscurity. He left Rome, not as the result of any crimes of his own, but of vicious betrayal by Agostino Tassi, his collaborator in the frescoes he had been painting for Cardinal Scipio Borghese. He learnt that his trusted fellow-artist had repeatedly violated his adolescent daughter Artemisia whilst professing to give her lessons in perspective. At the end of the consequent trial, during which Artemisia was tortured to establish her truthfulness, Tassi, who had influential friends, was sentenced to only eight months' imprisonment.

Resentful but cautious, Gentileschi eased himself out of Rome gradually, working in the churches beyond the boundaries of the city, and in Ancora and Fabriano, whilst he sought grander employment elsewhere. He applied without success for posts in Florence and Venice before accepting the hospitality of a Genoese patrician in 1621. From Genoa he presented a picture (which was his usual way of seeking preferment) to the Duke of Savoy, but in vain. He tried the same method with his compatriot, Marie de Medici, the Queen Mother of France, and this time was successful, moving to Paris in 1624; but not caring for her court, he followed her daughter, Henrietta Maria, now Queen of England, to London two years later. There he settled, although in his restlessness, now habitual, he tried to tempt both the Grand Duke of Tuscany (another Medici) and Philip IV of Spain with girls of pictures. The painting he sent Philip IV is included in the small but weighty exhibition in the Sunley Rooms at the National Gallery, Orazio Gentileschi at the Court of Charles 1, which represents his work well, since he was not prolific, and painted little of importance until he was nearly forty years old. From the age of sixty-two his time was taken up by his decorations for the house built for Queen Henrietta Maria at Greenwich in 1635 by Inigo Jones. The exhibits are described here in, as far as can be surmised, chronological order.

The earliest and the most violent picture, from the first decade of the seventeenth century, is the closest to Caravaggio. A flyweight David, his adolescent face flushed and eager, has dropped his sling and swung aloft Goliath's sword, which is only a little short of David's height. He stands with one fight-grimed foot on the shirking bulk of the giant. The sky darkens over the ravaged battlefield and the champion of the Philistines. The final blow of the victor is at least suspended. Artemisia would have preferred a gory decapitation, perhaps as vicarious revenge on the man who raped her. In Orazio's Mocking of Christ violence is only incipient, although blood drips from the crown of thorns and he is manhandled by a pair of dark, lewd-faced bullies, who clearly take a sinister delight in Jesus's perplexity.

The prosaic honesty of Gentileschi's Rest on the Flight persuades one that this is what it was really like. Tired out and footweary, Joseph sprawls and snorts, asleep in the shade of a crumbling wall. Mary, though herself dropping with weariness, props herself up with one hand in the dust to suckle her infant. Behind the wall their donkey dozes on its feet. Akin to this canvas and with the same sand-eroded wall is Gentileschi's delicate copper-painting of The Madonna in a Landscape - more, in fact, in a skyscape. A wispy indigo dawn, tangled with skeins of dim pearl, slate blue and apricot, floods the auburn disarray of Mary's hair. The penumbra behind her head is the nearest thing to a halo Gentileschi ever painted. She struggles with her exhaustion, solicitous to wrap a shawl around her child, and half-drowses, though in a self-sacrificing posture: one of her bare feet, grimy from the desert soil, balances on the other, so that she may buttress the child's back with her thigh as he sleeps against her arm.