An agreement brokered by U.S. Ambassador Dwight Whitney Morrow ends the Cristero War in Mexico.

Dwight Whitney Morrow was an American businessman, diplomat, and politician, best known as the U.S. ambassador who improved U.S.–Mexico relations, mediating the religious conflict in Mexico known as the Cristero rebellion (1926–29), but also contributing to an easing of conflict between the two countries over oil. The Morrow Mission to Mexico was an "important step in the 'retreat from imperialism.' " He was the father of Anne Morrow and father-in-law of Charles A. Lindbergh.

The Cristero War, also known as the Cristero Rebellion or La cristiada, was a widespread struggle in central and western Mexico from 3 August 1926 to 21 June 1929 in response to the implementation of secularist and anticlerical articles of the 1917 Constitution. The rebellion was instigated as a response to an executive decree by Mexican President Plutarco Elías Calles to strictly enforce Article 130 of the Constitution, an implementing act known as the Calles Law. Calles sought to limit the power of the Catholic Church in Mexico, its affiliated organizations and to suppress popular religiosity.