The Cristero War or Cristero Rebellion (1926–1929), also known as La Cristiada, was a widespread struggle in many central-western Mexican states against the secularist, anti-Catholic, and anticlerical policies of the Mexican government. The rebellion was set off by enactment under President Plutarco Elías Calles of a statute to enforce the anticlerical articles of the Mexican Constitution of 1917 (also known as the Calles Law). Calles sought to eliminate the power of the Catholic Church and organizations affiliated with it as an institution, and also suppress popular religious celebration in local communities. The massive, popular rural uprising was tacitly supported by the Church hierarchy and was aided by urban Catholic support. US Ambassador Dwight W. Morrow brokered negotiations between the Calles government and the Church. The government made some concessions, the Church withdrew its support for the Cristero fighters and the conflict ended in 1929. It can be seen as a major event in the struggle between Church and State dating back to the 19th century with the War of Reform, but it can also be interpreted as the last major peasant uprising in Mexico following the end of the military phase of the Mexican Revolution in 1920.