This work is sold with a group of 14 letters between Sigmund Firestone and Diego Rivera and Frida Kahlo dating from January 1940 to August 1941. Also included is one letter from Heinz Berggruen addressed to Sigmund Firestone. The correspondence chain is as follows:
January 9, 1940, from Firestone to Diego Rivera.
February 15, 1940, from Frida Kahlo to Firestone.
March 9, 1940, from Firestone to Frida Kahlo.
July 5, 1940, from Firestone to Diego Rivera.
September 27, 1940, from Heinz Berggruen to Firestone.
October 2, 1940, from Firestone to Frida Kahlo.
Circa end of October, 1940 (answered 3 weeks after the previous letter was received), from Frida Kahlo to Firestone.
November 2, 1940, from Firestone to Frida Kahlo.
December 9, 1940, from Frida Kahlo to Firestone.
January 8, 1941, from Diego Rivera to Firestone.
January 11, 1941, from Firestone to Diego Rivera.
January 30, 1941, from Diego Rivera to Firestone.
February 6, 1941, from Firestone to Diego Rivera.
July 18, 1941, from Diego Rivera to Firestone.
August 15, 1941, from Firestone to Diego Rivera.
On January 9, 1940, Sigmund Firestone wrote to Rivera, "I trust that by this time you and Frida are busy painting yourselves for my benefit. Please make them both on the same size canvas as I intend to always keep them together in memory of our pleasant acquaintanceship." Firestone, an American engineer and art collector from Rochester, New York, met Rivera and Frida Kahlo on a business trip to Mexico in 1939. Stirred by his visit to the couple's studio, Firestone commissioned companion portraits as a memento of their meeting. The commission for the pendant self-portraits, of similar proportions and complementary palette, came nevertheless while the Riveras were separated from each other. The divorce became final on January 9, 1940, although the couple remained friendly and would marry for a second time later that year on December 8, Diego's fifty-fourth birthday.
Kahlo continued to handle Rivera's business correspondence during their separation, and on February 15, 1940 she replied to Firestone on Riveras behalf because, she explained, "his English is lousy and he is ashamed to write." Kahlo wrote that her portrait was finished and that she would send it as soon as Rivera finished his. She admitted "some troubles" of her own, an allusion to the physical, emotional and financial difficulties she faced during the time of the separation, and described the situation with a resigned understanding:
Diego is happier now than when you saw him. He eats well and sleeps well and work [sic] with great energy. I see him very often but he doesn't want to live in the same house with me anymore because he likes to be alone and he says I always want to have his papers and other things in order, and he likes them in disorder. Well anyway I take care of him the best I can from the distance, and I will love him all my life even if he wouldnt want me to.
Saddened and subdued, Kahlo nevertheless signed the letter with her signature magenta-pink kisses, one for "Sigy" and one each for his daughters Alberta and Natalie, and enclosed bright pink feathers as a token of her affection.
Rivera recounted the period of separation with self-deprecating candor in his autobiography, years later:
I never was a faithful husband, even with Frida. As with Angeline and Lupe, I indulged my caprices and had affairs. Now, moved by the extremity of Frida's condition, I began taking stock of myself as a marriage partner. I found very little which could be said in my favor. And yet I knew I could not change. . . . I loved her far too much to want to cause her suffering, and to spare her further torments, I decided to separate from her. . . . We had been married now for thirteen [in fact, ten] years. We still loved each other. I simply wanted to be free to carry on with any woman who caught my fancy.
An admitted and incorrigible philanderer, Rivera nevertheless asked Kahlo to consider remarriage several times in the months following the divorce; and at last she consented, writing to Firestone in November 1940, "I will go back to San Francisco and marry Diego again." (He wants me to do so because he says he loves me more than any other girl). . . . We will [be] together again, and you will have us together in your home."
The Riveras remarried on Frida's terms, though none of them would withstand the test of time. Diego recalled that Frida:
asked for certain conditions: that she would provide for herself financially from the proceeds of her own work; that I would pay one half of our household expenses nothing more; and that we would have no sexual intercourse. . . . I was so happy to have Frida back that I assented to everything.
Frida's desire for financial self-sufficiency is evidenced in the Firestone commission, for which they were to share equally the $500 payment. Diego moved into the Casa Azul with Frida upon their return to Mexico in 1941, and their marriage lasted in spite of many infidelities on both sides until Kahlo's death fifteen years later. "We will be together on your wall," Frida wrote to Firestone, "as a symbol of our remarriage."
Rivera alternated mural painting with private commissions throughout his career, painting constantly, and he delayed completing his part of the Firestone commission due to ongoing work on the mural, Pan American Unity, for the Golden Gate International Exposition at Treasure Island in San Francisco. He began the self-portrait in 1941 while staying in Santa Barbara, where he had use of the studio of Frances Rich, an American sculptor and daughter of the actress, Irene Rich. Frances later recounted that her mother was so enchanted by the self-portrait in progress that she implored Rivera to sell it to her, which he did. Rivera then began work on a second self-portrait, nearly identical, which he dedicated to Sigmund Firestone in January 1941. "I have delayed much too long in sending my self portrait to you," Rivera admitted to Firestone on January 8, 1941, but he promised to send it as soon as possible.
"Portraiture makes up a significant part of the work of Diego Rivera," Xavier Moyssén has observed, "especially if one includes the portraits of historic personages that appear in his murals." Rivera's self-portraits occupy a special place in his oeuvre, collectively constituting what Moyssén has called a "visual autobiography that reveals all the vicissitudes of human experience." Rivera painted himself approximately twenty times between 1906, the time of his studies at San Carlos Academy, and 1951, the year of his last known self-portrait. Although he occasionally painted himself in full or half-length, the majority of his self-portraits feature his face alone, rounded and sturdily built. Painted with unflinching realism, Rivera's face peers out of the Firestone self-portrait with mature self-consciousness, his left eye drooping just slightly behind his glasses. His large, expressive eyes convey an accumulated wisdom and gentle introspection, here turning inward, away from the greater social world that they so often, acutely observed.
In the Firestone self-portrait, Rivera draws on a palette of warmly resonant colors, drawing out harmonies of complementary tones in stippled taches of paint. The mottled background recalls the Cubist studies of his Parisian years, yet the luminosity of the colors brilliantly aglow in the highlights of his hair and the shadows of his face suggests a mature handling of paint and understanding of its expressive effects. The dedication to Firestone, which Rivera holds in his hand, nods to nineteenth-century Mexican portrait painting; and indeed Rivera stands with his contemporaries Orozco and Siqueiros as heirs to the venerable national tradition. Yet Rivera's self-portraits stand alone in their expressive candor and perceptive countenance, offering an intimate glimpse into the artist through his own eyes. The self-portraits of Diego Rivera reveal his long and fruitful career, from the monumental mural paintings to the most personal drawings, Moyssén has reflected. His self-portraits are perhaps the most psychologically profound of all his portraits, reflecting his aesthetic aims and revealing an intimate sense of the man, his desire to identify himself with heroes and intellectuals, and to achieve immortality.
 Sigmund Firestone to Diego Rivera, 9 January 1940.
 Frida Kahlo to Firestone, 15 February 1940.
 Diego Rivera, My Art, My Life: An Autobiography, New York: The Citadel Press, 1960, 225-26.
 Kahlo to Firestone, 1 November 1940.
 Rivera, My Art, My Life, 242-43.
 Kahlo to Firestone, 9 December 1940.
 Rivera to Firestone, 8 January 1841.
 X. Moyssén, "Diego Rivera: The Self-Portraits," Diego Rivera: A Retrospective, Detroit: Detroit Institute of the Arts, 1986, 189.
 Moyssén, "Diego Rivera: The Self Portraits," 195.