Due to the strict enforcement of anti-clerical laws, people in strongly Catholic areas, especially the states of Jalisco, Zacatecas, Guanajuato, Colima and Michoacán, began to oppose him, and this opposition led to the Cristero War from 1926 to 1929, which was characterized by brutal atrocities on both sides. Some Cristeros applied terrorist tactics, while the Mexican government persecuted the clergy, killing suspected Cristeros and supporters and often retaliating against innocent individuals. On May 28, 1926, Calles was awarded a medal of merit from the head of Mexico's Scottish rite of Freemasonry for his actions against the Catholics.