Explain the factors that led to Spain losing control of Mexico.

The Mexican War of Independence (Spanish : Guerra de Independencia de México) 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 the French invasion of Spain in 1808; it extended from the Grito de Dolores by Father Miguel Hidalgo y Costilla on September 16, 1810, to the entrance of the Army of the Three Guarantees led by Augustín de Iturbide to Mexico City on September 27, 1821. September 16 is celebrated as Mexican Independence Day.