This resulted not only in the Bestiario series of drawing and wood block prints, but established a style of painting that is now incorporated into the Oaxacan School. While in Paris, Nieto won the Biennale de Paris Prize for painting in 1963. He again won the Biennale de Paris Prize for painting in 1968. In 1966, Rodolfo Nieto illustrated “Manuel de zoologie fantastique” by Jorge Luis Borges. Nieto won the Bienal of Caen in 1970 and the Bienal de Menton. He returned to Mexico in 1972, stating that indigenous spirits called "nahuales" were calling him home. In Europe Nieto had gained fame and recognition in the art world, but in Mexico he struggled despite an exhibition of his work at the Museo de Arte Moderno in 1973. A sensitive man, Nieto was crushed emotionally that the Mexican art critiques refused to consider his work seriously. He met his wife, Nancy Glenn-Nieto, a painter, at the grand opening of David Alfaro Siqueiros Polyforum Cultural Siqueiros in Mexico City. Nieto was invited to Siqueiros' home after the Polyforum event and asked Siqueiros if he could bring along his new friend. Siqueiros said, "Of course." But Nancy preferred to spend time alone with Nieto. Later Nancy regretted not attending Siqueiros' private party. Nancy and Nieto were wed a few months later.2 The new couple developed a deep connection with art, especially Nieto's new genre of Mexican art. However, Mexico was not ready for Nieto's art. “Because Mexico rejected his art, Rodolfo went into a deep depression.”2  Rodolfo and Nancy pressed on. They painted together every day, from the morning until often late into the evening. Nancy helped Nieto stretch and gesso the canvases, sketch the major constructions lines and Nieto would finish the work. Together they created hundreds of paintings. With the frenzy of work, Nieto became exhausted and depressed. His sleeping was erratic, his mind began wondering, seeing things, speaking and acting unusual. He seemed to have an awareness of his life coming to an end. In the Mexican tradition of laughing at death with skull art he began to paint Calaveras (skulls) in the Nieto tradition of mentally taking apart the structural elements only to reassemble them in a different perception. His brief life ended on June 24, 1985.