1531 — Juan Diego, one of the first Christianized Aztecs, reports the appearance of the Virgin of Guadalupe. 

1551 — National university is founded in Mexico City.

1808 — Napoleon dethrones the Spanish king, stimulating policial unrest throughout Spain’s empire.

1810–c. 1821 — During wars of independence that pit Mexicans against one another as well as the forces of Spain, over 12 percent of Mexican population dies. Mexican independence is achieved under the 1821 Plan of Iguala, which promises equality for citizens and preserves the privileges of the Catholic Church.

1821 — Moses Austin receives land grant to settle Anglo-Americans in Texas.

1824 — Constitution of 1824 establishes Mexico as a republic with a federal system.

1825 — Joel R. Poinsett is named the first United States minister to Mexico. At the first Pan-American congress in 1826, Mexico’s representative defeats Poinsett’s plans for a hemisphere-wide trade pact, interpreting it as a cover for United States dominance.

1835 — Rebels seeking independence for Texas fight the Mexican army at the Alamo. In 1836 the Texas Republic becomes independent.

1837–1841 — Revolts favoring federalism over the centralizing constitution imposed by Antonio López de Santa Anna in 1836 occur in much of Mexico.

1845 — The United States annexes Texas.

1846–1848 — Mexico and the United States are at war. In the resulting treaty of Guadalupe-Hidalgo, Mexico cedes Texas, New Mexico, and California to the United States.

1854 — United States Senate approves Gadsden Purchase from Mexico, adding nearly 30,000 square miles to southern Arizona and New Mexico.

1854–1861 — Benito Juárez and other liberals overthrow Santa Anna (Revolution of Ayutla). The liberal reforms they inaugurate encourage division of Indian and church lands into private holdings, subject clergy and military to regular courts, and establish religious freedom.

1857 — Constitution establishes a federal republic and, moving beyond the Constitution of 1824, guarantees the individual rights of free speech, assembly, and press. In 1858–1861 supporters and opponents of the reforms fight the War of the Reform, which ends in liberal victory.

1862–1867 — The French emperor Napoleon III, in alliance with conservative and proclerical Mexicans, installs Maximilian of Habsburg as emperor of Mexico. On May 5, 1862, Mexican troops defeat Napoleon III’s troops at Puebla. (The holiday Cinco de Mayo honors this victory.) In 1867 Juárez’s forces defeat and execute Maximilian.

1876–1911 — The Porfiriato, the authoritarian regime of the longtime president Porfirio Díaz, maintains the liberal economic policies and secularization achieved under Juárez and encourages foreign investment.

1884 — United States–Mexican railroad connection links El Paso and Mexico City.

1891 — United States Immigration Act authorizes inspection stations at ports of entry on the Mexican and Canadian borders.

1904 — To curtail undocumented entry of Asian and European immigrants into the United States through Mexico, immigration inspectors on horseback begin to patrol the United States–Mexican border.

1910–1917 — Spurred by discontent with the dictatorial Díaz regime, regional animosities, and increasing economic inequality in the countryside, guerrilla armies fight the Mexican Revolution, temporarily breaking the country into warring regions.

1914 — United States forces occupy the port city of Veracruz for seven months.

1916 — United States President Woodrow Wilson orders Gen. John Pershing to capture guerrilla leader Pancho Villa after Villa’s attack on Columbus, New Mexico. For nine months 4,000 American troops search in vain for Villa.

1917 — The Constitution of 1917 maintains republican and liberal features of the 1824 and 1857 constitutions but also guarantees social rights such as a living wage. It nationalizes mineral resources and prohibits foreign businessmen from appealing to their home governments to protect their property. Altered many times, this constitution remains in force.

1917 — The United States Immigration Act applies a literacy test and head tax to Mexicans entering the United States legally, spurring undocumented immigration by Mexican workers. (During the World War I labor shortage, these provisions are temporarily suspended.)

1918 — Oil is declared an inalienable national resource, and existing titles to oil lands become concessions. The United States government protests.

1924 — The Immigration Act of 1924 establishes the United States Border Patrol.

1927 — Conflict over the 1917 Constitution’s provisions for separation of church and state leads to nationalization of church property and armed rebellion, which the government suppresses.

1929 — President Plutarco Elías Calles founds the predecessor to the Partido Revolucionario Institucional (PRI). The PRI controls the national government throughout the next seven decades.

1929–1934 — Nearly 500,000 Mexican nationals and some Mexican Americans are repatriated to Mexico, forcibly or voluntarily, during the Great Depression.

1933 — President Franklin D. Roosevelt announces the Good Neighbor Policy, promising to end United States military intervention in Latin American countries.

1933–1934 — Mexican painter Diego Rivera, a Marxist, completes murals for the RCA building in Rockefeller Center, New York City. When he refuses to replace the face of Lenin with that of an anonymous individual, as requested by Nelson Rockefeller, the murals are destroyed.

1937–1938 — Mexico nationalizes British and United States railroad and oil industries. A 1947 settlement provides compensation to foreign investors.

1940s — El Congreso de Pueblos que Hablan Español (congress of Spanish-speaking peoples) calls for the relaxation of United States restrictions on immigration, naturalization, and citizenship.

1942 — The United States and Mexico adopt the Emergency Farm Labor Program, or bracero program, allowing Mexicans to perform contract work in the United States for a fixed period. Over the next 22 years of the program’s existence, more than 4.6 million labor contracts are issued.

1957 — Citizens of El Paso, Texas, elect the first Mexican American mayor of a US city.

1968 — Riot police repress student protests for democratization of the government, killing over 100 civilians in the massacre of Tlatelolco in Mexico City.

1970–1976 — Mexican President Luis Echeverría visits Cuba and the Soviet Union and engineers a partial lifting of the hemispheric embargo against Cuba.

1973 — United States creates the Drug Enforcement Administration (DEA) to suppress domestic and foreign production of narcotics intended for sale in the United States.

1982 — President José Lopez Portillo visits Nicaragua and praises the Sandinista revolution.

1986 — The Immigration Reform and Control Act (IRCA), or Simpson-Rodino Act, increases funds for the United States Border Patrol, penalizes employers for hiring unauthorized workers, and provides amnesty to long-term undocumented residents.

1986 — The Anti–Drug Abuse Act enhances the DEA’s power to extradite foreign drug traffickers and prosecute them in the United States.

1990 — The Mexican Secretariat of Foreign Affairs creates the Program for Mexican Communities Abroad to aid Mexicans in adapting to life in the United States and to foster continuing ties to the homeland.

1994 — The North American Free Trade Agreement (NAFTA) begins to phase out tariffs between the United States, Canada, and Mexico over fifteen years.

1994 — Zapatista rebellion in Chiapas, Mexico, protests the PRI’s dominance of political power and the government’s indifference to the fate of peasants and indigenous peoples.

1994 — California voters adopt Proposition 187, denying undocumented residents access to nearly all public services in the state. (Courts later strike down much of the law as unconstitutional.)

1995 — Over 500,000 Mexicans work in maquiladoras, factories on the border that assemble parts from the United States and export the finished goods back to the United States.