At the age of eighteen, Siqueiros and several of his colleagues from the School of Fine Arts joined Venustiano Carranza's Constitutional Army fighting the government of President Victoriano Huerta. When Huerta fell in 1914, Siqueiros became enmeshed in the "post-revolutionary" infighting, as the Constitutional Army battled the diverse political factions of Pancho Villa and Emiliano Zapata for control. His military travels around the country exposed him to Mexican culture and the raw everyday struggles of the working and rural poor classes. After Carranza's forces had gained control, Siqueiros briefly returned to Mexico City to paint before traveling to Europe in 1919. First in Paris, he absorbed the influence of cubism, intrigued particularly with Paul Cézanne and the use of large blocks of intense color. While there, he also met Diego Rivera, another Mexican painter of "the big three" just on the brink of a legendary career in muralism, and traveled with him throughout Italy to study the great fresco painters of the Renaissance.