Mexican War of Independence
The Mexican War of Independence () was an armed conflict, and the culmination of a political and social process which ended the rule of Spain in 1821 in the territory of New Spain. The war had its antecedent in Napoleon's French invasion of Spain in 1808; it extended from the Cry of Dolores by Father Miguel Hidalgo y Costilla on September 16, 1810, to the entrance of the Army of the Three Guarantees led by Agustín de Iturbide to Mexico City on September 27, 1821. September 16 is celebrated as Mexican Independence Day.
American frontier
Mexico became independent of Spain in 1821, and took over Spain's northern possessions stretching from Texas to California. Caravans began delivering goods to Mexico's Santa Fe along the Santa Fe Trail, over the journey which took 48 days from Kansas City, Missouri (then known as Westport). Santa Fe was also the trailhead for the "El Camino Real" (the King's Highway), a trade route which carried American manufactured goods southward deep into Mexico and returned silver, furs, and mules northward (not to be confused with another "Camino Real" which connected the missions in California). A branch also ran eastward near the Gulf (also called the Old San Antonio Road). Santa Fe connected to California via the Old Spanish Trail.