April 15th of 1940
Hotel Ritz, Mexico City.
I am most happy to accept your kind invitation to participate in the G.G.I.E. and paint a fresco in the Palace of Fine Arts, on the condition that I be permitted to make this my personal contribution toward the promotion of good will between our countries and because of my great affection for my friends in San Francisco who made my previous stay in San Francisco such a pleasant one.
For years I have felt that the real art of the Americas most came as a result of the fusion of the machinism and new creative power of the north with the tradition rooted in the soil of the south, the Toltecs, Tarascans, Mayas, Incas, etc., and would like to choose that as the subject of my mural.
I am enthusiastic about this project and shall look forward eagerly to the pleasure of again seeing and being with you and my many other friends in San Francisco.