Siqueiros was one of the three founders of the modern school of Mexican mural painting. He was active as a painter and as Marxist political and artistic activist. Siqueiros is known for his radical approach to art, his new mural techniques make him one of the most influential artists of international muralist movement. He studied art at the San Carlos Academy and went to fight in the army in 1913 during Mexican Revolution. During the Spanish Civil War he commanded brigades for the Republicans. Alfaro Siqueiros later continued his art studies in Europe and returned to Mexico in 1922 where he painted several murals in government buildings.