<P> Mexican muralism was the promotion of mural painting starting in the 1920s, generally with social and political messages as part of efforts to reunify the country under the post Mexican Revolution government . It was headed by "the big three" painters, Diego Rivera, José Clemente Orozco and David Alfaro Siqueiros . From the 1920s to about 1970s a large number of murals with nationalistic, social and political messages were created on public buildings, starting a tradition which continues to this day in Mexico and has had impact in other parts of the Americas, including the United States where it served as inspiration for the Chicano art movement . </P> <P> Mexico has had a tradition of painting murals, starting with the Olmec civilization in the pre Hispanic period and into the colonial period, with murals mostly painted to evangelize and reinforce Christian doctrine . The modern tradition has its roots in the 19th century, with this use of political and social themes . The first Mexican mural painter to use philosophical themes in his work was Juan Cordero in the mid 19th century . Although he did mostly work with religious themes such as the cupola of the Santa Teresa Church and other churches, he painted a secular mural at the request of Gabino Barreda at the Escuela Nacional Preparatoria (since disappeared). </P> <P> The latter 19th century was dominated politically by the Porfirio Díaz regime . This government was the first to push for the cultural development of the country, supporting the Academy of San Carlos and sending promising artists abroad to study . However, this effort left out indigenous culture and people, with the aim of making Mexico like Europe . Gerardo Murillo, also known as Dr. Atl, is considered to be the first modern Mexican muralists with the idea that Mexican art should reflect Mexican life . Academy training and the government had only promoted imitations of European art . Atl and other early muralists pressured the Diaz government to allow them to paint on building walls to escape this formalism . Atl also organized an independent exhibition of native Mexican artists promoting many indigenous and national themes along with color schemes that would later appear in mural painting . The first modern Mexican mural, painted by Atl, was a series of female nudes using "Atlcolor" a substance Atl invented himself, very shortly before the beginning of the Mexican Revolution . Another influence on the young artists of the late Porfirian period was the graphic work of José Guadalupe Posada, who mocked European styles and created cartoons with social and political criticism . </P>

Where did the mexican muralist movement get their inspiration
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