Spain had been very oppressive and had disrespected Mexico. Their relations were very tense and native Spaniards who had exploited and oppressed Mexicans for ten generations.
A parish priest named Father Hidalgo had initiated the "Cry of Dolores" which is also known as Grito De Dolores. Since this was treason, Hidalgo was soon killed but his cry had sparked a stronger hate against Spain
Mexican War of Independence September 16, 1810 – 1821 Spanish Viceroy Juan de O’Donojú signs the Treaty of Córdoba, which approves a plan to make Mexico an independent constitutional monarchy.