In September 1940, less than three months after Paris had surrendered to Hitler’s armies, artist Henri Matisse, stranded in Nice on the Mediterranean coast, sent a moving letter to his younger son, Pierre, in New York City, explaining why he now needed a model to paint more than ever. France was humiliated and defeated. Like millions of other citizens driven from their homes by the German invaders, Matisse had fled south, taking no more than he could carry, living precariously from one day to the next, and ending up in Nice, where a nervous population expected imminent invasion by Fascist Italian troops.

Matisse was 70, sick, helpless, fearful for his family and friends, and appalled by what had happened to his country. All he could do was work, but he said he dreaded the daily confrontation with form and color on canvas so much that he couldn’t face it without the consoling human presence of the pretty young film extras he paid to pose for him. That’s what keeps me there, surrounded by my fruit and flowers which I get to grips with little by little, almost without noticing . . . and then I wait for the thunderbolt that is bound to follow.”

The French expression for thunderbolt—coup de foudre—means “love at first sight,” with all the undertones of violence and risk that were an intrinsic part of Matisse’s passion for painting. Anxiety and dread hung over his studio sessions. Toward the end of his life he told an interviewer that each canvas began as a flirtation and ended up as a rape. He said it was himself, not his subject—or rather it was the feelings his subject aroused in him—that had to be raped. The subject itself could be fruit, flowers or a fabric screen, as often as a human sitter. The young women who posed for him all learned to live and work in the atmosphere of almost unbearable tension generated by Matisse’s effort to express his emotions on canvas—an effort that drained all his strength.

It was precisely his aura of desperation and danger that had first attracted Matisse’s wife, Amélie, who posed for or presided over every one of the great revolutionary canvases he produced in the first years of the 20th century. “As for me, I’m in my element when the house burns down,” she said coolly, in response to the howls of outrage provoked by her husband’s work. The riotous colors of his Woman in a Hat and Portrait of Madame Matisse, both painted in 1905, unnerved contemporaries. His notorious Blue Nude—a fiercely distorted picture of Amélie reclining in a sunlit glade beneath palm fronds—seemed grotesque and obscene when it was first shown in Paris in 1907. Even to Matisse’s faithful supporter, the young American critic Walter Pach, it felt like a punch between the eyes.

Matisse’s reputation as a Modernist leader was built on this sort of shock. So his followers saw it as an unforgivable betrayal when he moved from Paris to Nice ten years later and started painting good-looking young women in transparent tops and harem pants lounging on cushioned divans. “He’s given in, he’s calmed down, the public is on his side,” Matisse’s friend, politician and collector Marcel Sembat, wrote in disgust when the French state bought Odalisque in Red Culottes in 1922. Sembat’s view of Matisse at this stage as an essentially frivolous and decorative lightweight would set the tone of response to his work for decades to come. It was useless for Matisse himself to protest that his odalisque paintings of the 1920s and ’30s were a series of chromatic experiments, a long, grueling preparatory phase without which he could not have produced the astonishing cut-and-painted paper compositions constructed directly from color in the last decade of his life. The conventional verdict dismissed him, at the time and afterward, as a kind of 20th-century Fragonard, turning out sexy pictures for rich men’s Manhattan apartments and villas in the south of France.

Matisse himself knew perfectly well that the erotic charge in his work came from a passionate desire that overrode straightforward lust. It was painting itself that seduced him over and over again with each fresh canvas. In old age when he was too weak to stand all day at the easel, he feared going blind as well “because of having flirted for too long . . . with these enchanted colors.”

All his life Matisse drove his models as well as himself to the limits of endurance. He insisted it was better to risk ruining a painting than be satisfied with a surface likeness. It’s always necessary to force your whole being beyond this stage, he told his daughter, Marguerite, because it’s only then that you start to make discoveries, and tear yourself apart in the process.

Matisse paid with insomnia and panic attacks for his inability ever to be satisfied with what he could already do. The models were generally exhausted, sometimes mutinous, often apprehensive in the early years, when they had to come to terms not only with public ridicule but with their own private misgivings. Even the boldest, Matisse’s student Greta Moll, was horrified to find her features discolored and her limbs distorted on Matisse’s canvas. Amélie herself wept in distress when she saw the last painting he ever made of her, the grave and beautiful Portrait of Madame Matisse of 1913, with stony black eyes set in a delicate masklike gray face.

It took courage to pose for the extraordinary portraits Matisse made before World War I: The Girl with Green Eyes, The Algerian Girl, Girl in Green, Girl with Black Cat. The confident gaze and frank body language of these young women, painted almost a century ago, speak directly to us today, although contemporaries could see little in these portraits but meaningless jumbles of color outlined in ugly black brushstrokes. The sitters included the painter’s then teenage daughter, Marguerite (always one of his favorite models), and two of his students. But the one he returned to most often was a professional model named Loulou Brouty, who spent a whole summer with the Matisses in a remote Mediterranean fishing village in 1909. The entire family liked Brouty. She amused the children (Marguerite, Jean and Pierre), was company for Amélie, and took swimming lessons from Henri between painting sessions. She was a typical Parisienne, earthy and tough, with dark hair, catlike features, a lithe body and skin so richly tanned by summer’s end that Matisse’s pupils nicknamed her “the Italian sunset.”

The pictures he painted of Brouty startled everyone, including the painter himself. Marcel Sembat and his wife bought one of them, a seated nude that made them scream out loud the first time they saw it. “We had come across a strange little canvas,” wrote Sembat, “something gripping, unheard of, frighteningly new: something that very nearly frightened its maker himself. On a harsh pink ground, flaming against dark blue shadows reminiscent of Chinese or Japanese masters, was the seated figure of a violet-colored woman. We stared at her, stupefied. . . all four of us.” Sembat said afterward that the picture only made sense once you stopped trying to read it as a conventional nude and responded instinctively to the sensations of dazzling light, heat and shade conveyed by its patchwork of colors. “You see, I wasn’t just trying to paint a woman,” Matisse explained. “I wanted to paint my overall impression of the south.”

The story illustrates exactly what Matisse meant when he said he needed a model to humanize the ordeal of painting. In 1905 it was his wife who stared calmly out from conflagrations of blazing color on canvases that looked to the public and critics like the work of a wild beast. In 1909 it was the sturdy, self-possessed Brouty who pointed the way to a new visual language that would lead eventually to the somber, powerful, semiabstract works Matisse produced at the height of the carnage during WorldWarI. Toward the end of the war, when he had gone as far as it was possible to go at that stage toward abstraction, he turned to another professional model, this time an Italian called Lorette.

There was nothing in the least alluring about The Italian Woman, Matisse’s first painting of Lorette, with her hollowcheeks, sticklike bare arms and cheap, flimsy blouse. The picture’s geometrical construction of black lines and curvessomehow emphasized the touching pathos of this sad andwary hired model, dressed in an outfit hopelessly unsuited tothe freezing temperatures of a Paris winter. The Italian Woman was the last of a series of canvases in which Matissehad stripped painting down to its purest and most austere form. Now he was restless, and ready to throw off the constraints of abstraction. It was at this point that Lorette’s professional training as a model kicked in to liberate both of them. She adored dressing up, switching from waiflike innocence to sumptuous abandon, seeming to change mood, age, even size, as readily as she tried on costumes. Matisse painted her as a flirtatious Spanish señorita in a lace mantilla, a turbaned inhabitant of a Turkish harem and a Parisian cocotte.

He responded to Lorette’s lead as spontaneously as a dancer taking to the floor, painting her energetically from odd angles in strange perspectives, and improvising endlessly inventive rhythmic variations on the central theme of her strong features, heart-shaped face and black hair. Their relationship set a pattern for his future partnerships with models, each of which took on the obsessive intimacy of a love affair played out on canvas. Matisse painted Lorette nearly 50 times over a period of 12 months, breaking off only when he moved his workbase from Paris to a hotel in Nice in 1918.

It was over a year before he found anyone to take Lorette’s place in the provincial resort of Nice, where prospective models were so rare that painters had to wait in line for their services. Antoinette Arnoud was 19 years old, pale and slender, with worldly tastes and an inborn sense of French chic. Matisse responded to her love of style with a hat that he made himself from a cheap straw base with a white ostrich plume curling over the brim. Arnoud wore the new hat with a panache that made her simple white housecoat seem like a ball gown.

Daily painting sessions alternated with hours on end devoted to drawing. Matisse set himself the almost impossible task of retaining the concentrated simplicity and force of his work without sacrificing the sensual texture of fur, feathers, fabric or fluff. He returned over and over again to a lace collar, drawing it in minute detail (“each mesh, yes, almost each thread”) until he had got it by heart and could translate it at will with two swift lines “into an ornament, an arabesque, without losing the character of lace, and of that particular lace,” he once said. The same process was repeated with her embroidered tunic, hat, hair, hands and face. Energy pulses between the lines of the letters Matisse wrote home from the small hotel room in Nice where he lived, slept and worked, having finally succeeded in narrowing his existence down to painting alone. “I’m the hermit of the Promenade des Anglais,” he announced with pride to his wife.

For the public, the quality of Matisse’s pictures at this stage was more or less completely obscured by the lifestyle they depict. French Window at Nice shows Arnoud, with bare legs, long loose hair and scarlet harem pants, seated beside the bed in the painter’s hotel room. People drew the obvious (but as it now turns out, erroneous) conclusion from the fact that Matisse posed the young girls who sat for him in the 1920s amid all the trappings of an affair, endlessly painting one or another of them wearing a slip at the dressing table, half-dressed in a wrapper over a pot of coffee or newly emerged from the bath.

The painter himself said that these Nice interiors are suffused with sublimated sexual pleasure. He claimed that the intensity of his feelings discharged itself through the colors and forms orchestrated on canvas around the models’ bodies, and the evidence suggests this was true. In all the weekly, sometimes daily letters he exchanged during these years with his wife and children, there is nothing to suggest tension on this score, neither defensiveness on his part nor resentment on theirs. Matisse and his wife treated the succession of models in Nice as adoptive daughters. No one who knew him well at the time ever doubted that these women were working partners, not sexual conquests.

Sex, in fact, was one of the things Matisse grumbled about having to do without in Nice. So far as modeling went, he applied the same rules to human beings as to a fish dinner. “I’ve never sampled anything edible that had served me as a model . . . ,” he explained, describing a plate of oysters brought for him to paint from a nearby café by a waiter, who later fetched them back to serve to his customers at midday. Matisse said it never occurred to him to tuck into his oysters for lunch: “It was others who ate them. Posing had made them different for me from their equivalents on a restaurant table.”

The same seems to have been true of the models for his odalisque paintings of the 1920s. The first of these odalisques—sprawling in “harem costumes” on improvised divans—was Antoinette Arnoud’s successor, Henriette Darricarrère, who was working as an extra when Matisse spotted her in the film studios in Nice. He liked her natural dignity, the graceful way her head sat on her neck and, above all, the fact that her body caught the light like a sculpture. Aballet dancer and musician, Henriette became part of the family in the seven years she worked for Matisse. His wife grew especially fond of her, and he himself taught her to paint.

Matisse said it was essential to start by finding the pose that made any new model feel most comfortable. Henriette’s specialty was discovered by accident after a carnival party attended by Matisse and his daughter, dressed respectively as an Arab potentate and a beauty from the harem. Marguerite Matisse, Lorette, even Antoinette Arnoud, all tried on turbans and embroidered Moroccan tops, but it was Henriette, always modest, even prim, in her street clothes, who wore the filmy blouses and low-slung pants without inhibition, becoming at once luxuriant, sensual and calmly authoritative.

The pictorial possibilities she opened up for Matisse were enhanced by her exceptional sensitivity and stamina. He saw the work they produced together as an increasingly complex orchestration of colored light and mass, culminating in his Decorative Figure on an Ornamental Ground, which was almost as incomprehensible in 1926 as the BlueNude had been nearly 20 years earlier. The painting is a riot of exuberant trompe l’oeil wallpaper, flowers, fruit and patterned textiles, all pinned firmly in place by the pale upright figure of Henriette. She looked as impersonal and unyielding as a side of packaged butcher’s meat to Matisse’s friend, the painter Jules Flandrin, who was baffled and exhilarated in equal measure: “I can’t begin to convey the brilliantly successful contrast between the wallpaper flowers and the woman so skillfully mishandled,” he wrote to a friend. Soon after the completion of Decorative Figure, Henriette left to get married.

Over the next eight years Matisse gradually abandoned easel painting, experimenting with prints, inventing cut-paper techniques and working on large-scale decorative murals, until the advent of a new model in 1935. She was a Russian named Lydia Delectorskaya, and by her own account she could hardly have been more different from the dark-eyed, black-haired, olive-skinned southern types he had preferred until now. Lydia, who came from Siberia, had long golden hair, blue eyes, white skin and finely cut features: the looks of an ice princess, as Matisse said himself.

Born in 1910, the only child of a doctor (whom she adored), Lydia had been orphaned and forced to flee Russia in the turmoil after the 1917 revolution, ending up a penniless exile in Nice. She was surviving precariously on nothing but her pride, her resourcefulness and her unbudgeable will when, in 1932, she found temporary work, first as a studio assistant, then as a domestic, with Matisse and his wife. It was not for another three years that the painter asked her to sit for him. Lydia was 25, Matisse was 65. She thought of him as a kindly and polite old gentleman because (unlike previous artists, who had taught her to detest modeling) he never pawed at her or tried to take off her clothes. “Gradually I began to adapt and feel less ‘shackled,’ ” she wrote, “ . . . in the end, I even began to take an interest in his work.”

The first paintings Matisse made of Lydia combined the phenomenal virtuosity that had cost him so many years to perfect with his original instinctive ability to compose spontaneously in color. Matisse’s son Pierre told his father that he had renewed himself as a painter with Pink Nude, for which Lydia modeled over a period of six months in 1935.

That autumn Lydia posed for a drawing of a nymph being wooed by a satyr, a theme Matisse had first painted some 30 years earlier, when, as she said herself, his handling was far more brutal than in the variation he did of her. “With me, he knew how to be gentle and seductive. He was charming, and so touching. He knew how to tame me.” Matisse said he came eventually to know her face and body by heart, like the alphabet. The collaboration they established together gave Lydia a new sense of power and purpose. As she added the duties of studio manager to those of principal model, painting became the central core of her life as it was of Matisse’s.

It was their working alliance, rather than any question of adultery, that precipitated a crisis in Matisse’s marriage. Faced with an ultimatum from Amélie (“It’s me or her”), Matisse chose his wife and sacked Lydia, but it was too late. Amélie, still furious over what she viewed as his betrayal, left her husband early in 1939. Lydia, returning briefly to help out in the studio in Paris, found herself trapped with Matisse in a stream of people fleeing invasion after the declaration of war with Germany. “A decision had to be made there,” she said, “as to whether or not he was to take me with him.” Matisse drew Lydia in her traveling hood at the start of the long journey they were about to make together through war-torn France. She remained at his side for the rest of his life.

Visitors to Matisse’s studio never tired of speculating about the role of the beautiful, enigmatic secretary known as “Mme Lydia,” but few doubted that his survival depended on her, both as a man and an artist. In his closing decade in the face of exhaustion and failing health, Lydia made it possible for him to produce his final masterpieces—the chapel at Vence and the colored paper cutouts now generally agreed to be among the greatest inventions of the 20th century. Matisse died on November 3, 1954. He was 84. The day before, Lydia had come to his bedside with her newly washed hair wound in a towel turban, accentuating the classical severity and purity of the profile Matisse had so often drawn and painted. He sketched her with a ballpoint pen, holding the last drawing he ever made out at arm’s length to assess its quality before pronouncing gravely, “It will do.”