What did Spain do in 1821?

After 11 years of war, Spain granted Mexican independence as a constitutional monarchy.

On September 16, 1810, Miguel Hidalgo y Costilla, a Catholic priest, launched the Mexican War of Independence with the issuing of his Grito de Dolores, or "Cry of Delores." The revolutionary tract called for the end of Spanish rule in Mexico, redistribution of land, and racial equality.