those that emphasized Mexican rather than European themes. These were not created for popular or commercial tastes; however, they gained recognition not only in Mexico, but in the United States. "The great Mexican muralists of the post-revolution developed, with the paint mural, the concept of 'public art', an art to be seen by the masses in major public buildings of the time, and could not be bought and transported easily elsewhere, as with easel painting." This production of art in conjunction with government propaganda is known as the Mexican Modernist School or the Mexican Muralist Movement, and it redefined art in Mexico. Octavio Paz gives José Vasconcelos credit for initiating the Muralist movement in Mexico by commissioning the best-known painters in 1921 to decorate the walls of public buildings. The commissions were politically motivated—they aimed to glorify the Mexican Revolution and redefine the Mexican people vis-à-vis literally "face to face (with)" their indigenous and Spanish past. The first of these commissioned paintings were at San Ildefonso done by Fernando Leal, Fermín Revueltas, David Alfaro Siqueiros, and Diego Rivera. The first true fresco in the building was the work of Jean Charlot. However, technical errors were made in the construction of these murals: a number of them began to blister and were covered in wax for preservation. Roberto Montenegro painted the former church and monastery of San Pedro y San Pablo, but the mural in the church was painted in tempera and began to flake. In the monastery area, Montenegro painted the Feast of the Holy Cross, which depicts Vasconcelos as the protector of Muralists. Vasconcelos was later blanked out and a figure of a woman was painted over him. The first protagonist in the production of modern murals in Mexico was Dr. Atl. Dr Atl was born "Gerard Murillo" in Guadalajara in 1875. He changed his name in order to identify himself as Mexican. Atl worked to promote Mexico's folk art and handcrafts. While he had some success as a painter in Guadalajara, his radical ideas against academia and the government prompted him to move to more liberal Mexico City. In 1910, months before the start of the Mexican Revolution, Atl painted the first modern mural in Mexico. He taught major artists to follow him, including those who came to dominate Mexican mural painting. The muralist movement reached its height in the 1930s with four main protagonists: Diego Rivera, David