Highly developed cultures, including those of the Olmecs, Mayas, Toltecs, and Aztecs existed long before the Spanish conquest. Hernando Cortes conquered Mexico during the period 1519-21 and founded a Spanish colony that lasted nearly 300 years. Independence from Spain was proclaimed by Father Miguel Hidalgo on September 16, 1810; this launched a war for independence. An 1821 treaty recognized Mexican independence from Spain and called for a constitutional monarchy. The planned monarchy failed; a republic was proclaimed in December 1822 and established in 1824.

Prominent figures in Mexico's war for independence were Father Jose Maria Morelos; Gen. Augustin de Iturbide, who defeated the Spaniards and ruled as Mexican emperor from 1822-23; and Gen. Antonio Lopez de Santa Ana, who went on to control Mexican politics from 1833 to 1855. Santa Ana was Mexico's leader during the conflict with Texas, which declared itself independent from Mexico in 1836, and during Mexico's war with the United States (1846-48). The presidential terms of Benito Juarez (1858-71) were interrupted by the Habsburg monarchy's rule of Mexico (1864-67). Archduke Maximilian of Austria, whom Napoleon III of France established as Emperor of Mexico, was deposed by Juarez and executed in 1867. Gen. Porfirio Diaz was president during most of the period between 1877 and 1911.

Mexico's severe social and economic problems erupted in a revolution that lasted from 1910-20 and gave rise to the 1917 constitution. Prominent leaders in this period--some of whom were rivals for power--were Francisco I. Madero, Venustiano Carranza, Pancho Villa, Alvaro Obregon, Victoriano Huerta, and Emiliano Zapata. The Institutional Revolutionary Party (PRI), formed in 1929 under a different name, emerged as a coalition of interests after the chaos of the revolution as a vehicle for keeping political competition in peaceful channels. For 71 years, Mexico's national government had been controlled by the PRI, which had won every presidential race and most gubernatorial races until the July 2000 presidential election of Vicente Fox Quesada of the National Action Party (PAN).