If any man can be said to have changed the course of a nation's art single handed, it is Diego Rivera. He was born in 1886 in the Mexican silver mining town of Guanajuato. His father, a freemason with a 'liberal' background, was a teacher at the time of Diego's birth and later became a school inspector. Rivera was the elder of twin boys, but his brother died at the age of two. His family left his birthplace when he was six, driven out partly by the failure of certain mining speculations and partly by the unpopularity generated by his father's liberalism.

Rivera soon showed himself to be a precociously gifted artist and began to study in the evenings at the Academy of San Carlos at the age of ten. At sixteen Rivera joined a student strike at the Academy and was expelled. In due course he was officially reinstated, but never returned, instead working independently for the next five years.

Realizing that his son was getting nowhere in his chosen profession, Rivera senior helped Diego win a scholarship, awarded by the Governor of the Province of Veracruz, to study abroad. The young artist arrived in Spain in January 1907. Rivera made Spain his base for an extended tour which took in France, Belgium, Holland and England. He was in France in 1909, where he encountered the work of the Fauves and Cezanne, but he was later to claim that the artist who impressed him most was Henri Rousseau, 'Le Douanier' 'the only one of the moderns whose works stirred each and every fibre of my being.'

In 1910 he made a trip home, and held a successful exhibition in Mexico City. The wife of the powerful President of Mexico, Porfirio Diaz, bought six of the forty paintings shown, and a number more were purchased by the Academy of Fine Arts. But Diaz, who had been in power for thirty years, was about to fall. Rivera watched the revolution which displaced him and put the liberal Madero in power, but did not wait for subsequent events; he returned to Paris in 1911. Rivera now made many friends in the cosmopolitan Parisian avant garde, and at one time even shared a studio with Modigliani, who painted some striking portraits of him. But his chief contacts were with the Russians, largely because he had two Russian mistresses - this was the beginning of his career as a great womanizer. He was also becoming a legend in his own right, less for his talent than for his gargantuan stature and appetites. The Spanish modernist writer Ramon Gomez de la Serna wrote thus of Rivera:

They told fantastic tales about him; that he had the ability to suckle young at his Buddhic breasts ... that he was all covered with hair, which must have been true because on the wall of his study, by a Russian woman artist, Marionne [Marievna Vorobiev Stebelska, one of Rivera's mistresses], who painted in his studio, in a man's suit, with the boots of a tigertamer and a lion's skin, was his portrait, nude, with legs crossed and covered in kinky hair.

From 1913 onwards Rivera was working within the orbit of Cubism. There was a particularly clear kinship between the work he was producing - still mostly landscapes - and the work of Robert Delaunay. The winter of 1917 was a time of emotional upheaval. The woman with whom he lived, Angelina Beloff, had a child. The baby was sickly (it died early in 1918), and Rivera, who resented the amount of attention Angelina gave to it, took himself off to her rival, Marievna, for five months. Marievna also became pregnant. Rivera was working like a demon, in isolation from his former friends and full of real or imaginary ills. It was soon after this that he decided to break with Cubism. in 1919 he set off for Italy with David Alfaro Siqueiros, who had just arrived from Mexico, using money provided by Alberto Pani, the Mexican Ambassador to France. Together they studied the frescoes of the great Italian masters, and discussed the future of Mexican art. The decision to go back to Mexico was made in 1921. The homecoming was an emotional moment. 'On my arrival in Mexico,' Rivera said, 'I was struck by the inexpressible beauty of that rich and severe, wretched and exuberant land.' In November 1921 he accompanied the Minister of Education, Jose Vasconcelos, on a visit to Yucatan, an area where pre Columbian influence was very strong. The two men got on well together, and Rivera was the first artist to be appointed when it was decided to experiment with murals at the Preparatoria (National Preparatory School). Rivera's first attempt was painted in encaustic, but he soon mastered traditional fresco technique, and shed stiff European allegories in favour of a new and popular style, where the influence of the Aztecs mingled with that of Cubism and Rousseau. At the same period Rivera joined the Communist Party, with which he was to have a long, complicated and stormy relationship. Right wing students rioted against the Preparatoria murals before they were completed, and Rivera was the only artist who stubbornly continued to work there, a pistol stuck in his belt. It was at this time that he attracted the attention of a ring leader amongst the younger girls, Frida Kahlo. She was later to become his second wife.

Rivera soon proved that he was hugely prolific as well as energetic and determined. In 1923 he began a second series of murals at the Ministry of Education - this enormous cycle was to consist Of 124 frescoes. He also embarked on a smaller cycle for the Agricultural School at Chapingo. His work was much criticized at home, but attracted increasing attention abroad. In 1927, when the murals at the Ministry of Education had at last been finished, Rivera was invited to go to Russia, for the tenth anniversary celebrations of the Revolution. He was flatteringly received in November he signed a contract with the Minister for Culture, Lunacharsky, to paint a mural for the Red Army Club in Moscow. But every now and then Rivera had a moment of discomfort, of which the most acute occurred when he met Stalin:

the Central Committee ... my fellow guests smirking with satisfaction, drooling with superiority ... they might have been entering paradise. ... Suddenly a peanut shaped head, surmounted by a military haircut, decked out with a magnificent pair of long moustaches, rose above them ... one hand slipped into his overcoat and the other folded behind him a la Napoleon. ... Comrade Stalin posed before the saints and worshippers.

Rivera's Russian hosts found him rather more of a handful than they had bargained for. He got on badly with the assistants assigned to him, and the much heralded mural project was soon at a standstill. In May 1928 a solution was found to what had become a dilemma: Rivera was ordered home by the Latin American Secretariat of the Comintern as a prelude to his expulsion from the Party in 1929. The year 1929 witnessed other momentous changes in his life. One reason for his eagerness to go to Russia was that he was tired of the tantrums of his first wife, the beautiful but termagant Guadalupe (Lupe) Marin. On his return home he decided to replace Lupe with his young admirer Frida Kahlo who was to become an important painter in her own right. Since he had gone through a church ceremony with Lupe, but never a civil one, the marriage was fairly easily dissolved, and he and Frida were married that August. in December he accepted a commission from the American Ambassador to Mexico to paint a series of frescoes in the loggia of the sixteenth century Palace of Cortez in Cuernavaca. The building, splendidly proportioned, set in a superb landscape and full of historic overtones, inspired Rivera to produce some of his most memorable and now best loved images.

In 1930 Rivera was invited to go to the United States, and decided to exploit his new found fame north of the border, despite a deep rooted suspicion of gringos. In November 1930 he arrived in San Francisco to paint a mural for the Stock Exchange. This was followed by a witty fresco for the California School of Fine Art showing the painter and his team at work: right at the centre of the composition is Rivera's enormous backside. He returned briefly to Mexico, then went to New York in November 1931 for a retrospective exhibition at the Museum of Modern Art. This was the Museum's fourteenth exhibition and only its second one man show - the first had been devoted to Matisse. It broke all previous attendance records and made Rivera and his wife into major American celebrities. His next stop was Detroit, where he had been invited to provide murals for the inner courtyard of the Detroit Museum. The reception given to them when they were officially unveiled in March 1933 was stormy, but Rivera and his partisans prevailed. The painter then moved back to New York to carry out a yet more prestigious commission - a mural for the RCA Building, part of the new Rockefeller Center. Rivera, more than ever filled with the spirit of provocation, and euphoric after his recent successes, tried the patience of his patrons too far by featuring a portrait of Lenin in his composition, which was supposed to depict 'Man at the Crossroads Looking with Hope and High Vision to the Choosing of a New and Better Future'. Work was abruptly halted and Rivera was paid in full according to his contract - which prevented him from having any further control over the fate of his work. It was first hidden from public view behind a curtain and then, despite assurances to the contrary, destroyed. The episode provided the biggest scandal of Rivera's career. He lingered for a while in New York, determined not to acknowledge defeat, filling his time painting a set of murals for the New Workers School and two small panels for the headquarters of the New York Trotskyites. Eventually he was forced to creep away with his tail between his legs.

After the New York fiasco Rivera found it difficult to secure commissions for murals, even at home. Between 1935 and 1943 he received no government co mmissions of any kind. The best he could get - in 1936 was a mural commission for the new Hotel Reforma in Mexico City, from his old patron, Alberto Pani. But here, too, there was a disagreement, and as a result the murals were altered without the artist's consent. Mexican laws on this subject being different, and stricter, than those which prevailed in the United States, Rivera was able to bring a suit for damages and win it.

Since his expulsion from the official Communist Party Rivera had sided with the Trotskyites, and when Trotsky and his wife arrived in Mexico in January 1937 the Riveras were amongst the first to welcome them. Frida Kahlo, who had already put up with many infidelities on her husband's part, became Trotsky's lover, though the affair was soon over. Another admirer, to whom she did not respond so positively, was the 'pope' of Surrealism, Andre Breton, who arrived in Mexico in 1938. The exact cause of Kahlo and Rivera's divorce in 1940 remains mysterious; but their lives were too much intertwined for them to remain apart, and they were soon remarried.

The late 1940s were marked by a series of humiliating attempts on Rivera's part to get back into the Communist party. He had quarrelled with Trotsky before the latter was assassinated, and the Mexican police even at one time suspected him of complicity in the crime. In 1946 Rivera made a major attempt to win the party's forgiveness, denouncing himself as a bad Communist, even saying that the quality of his work had suffered throughout the period of his separation from the Party. He was roundly rejected, and the same thing happened when he tried again a few years later. What counted against him was less his association with Trotsky than the fact that he had once painted an unflattering portrait of Stalin. He eventually grasped this, and when he was asked to provide a major work for the Mexican Exhibition in Paris in 1952 he produced a coarse piece of pro-Stalinist and anti-Western propaganda which contained a suitably heroic likeness of the Soviet leader. The Mexican government refused to exhibit it, since by implication it insulted the French government, and Rivera was rewarded with a satisfactory uproar in the French press.

In September 1954 he was finally re-accepted by the Communists. But this dubious success came a little late since earlier in the year he had lost Frida. Due to an appalling accident suffered when she was still an adolescent she had been in poor health for many years, and in the last period of her life was in constant pain and often bedridden. Her husband was shattered by the loss. He was not in good health himself, and in 1953 he used his re-acceptance by the Party to go to Russia for medical treatment. On his return he had yet another surprise in store for the Mexican public which avidly continued to follow his activities. Some years previously he had painted a mural for the Del Prado Hotel in Mexico City, one of his most delightful compositions. (This was seriously damaged in the earthquake of 1985) Called Dream of a Sunday Afternoon on the Central Alameda, it is an autobiographical work which shows the artist as a boy, hand in hand with a female skeleton in grand Edwardian costume - a typically gruesome piece of Mexican folklore. They are surrounded by characters from a fantastic paseo. The mural was kept covered after its completion because Rivera had included the slogan 'God Does Not Exist'. Now he ceremoniously painted out the offending words, thus announcing his reconciliation with the Church though the reconciliation somehow did not involve another breach with the Communist Party. With the opposing forces in his life, and in Mexican culture, now neatly in balance, Rivera died in November 1957.

- From Edward Lucie-Smith, "Lives of the Great 20th-Century Artists"