Mexican War of Independence
Iturbide's assignment to the Oaxaca expedition coincided with a successful military coup in Spain against the monarchy of Ferdinand VII. The coup leaders, part of an expeditionary force assembled to suppress the independence movements in the Americas, had turned against the monarchy. They compelled the reluctant Ferdinand to reinstate the liberal Spanish Constitution of 1812 that created a constitutional monarchy. When news of the liberal charter reached Mexico, Iturbide perceived it both as a threat to the status quo and a catalyst to rouse the criollos to gain control of Mexico. Independence was achieved when conservative Royalist forces in the colonies chose to rise up against the liberal regime in Spain; it was an about-face compared to their previous opposition to the peasant insurgency. After an initial clash with Guerrero's forces, Iturbide assumed command of the royal army. At Iguala, he allied his formerly royalist force with Guerrero’s radical insurgents to discuss the renewed struggle for independence.
Mexican War of Independence
After 1810 the independence movement went through several stages, as leaders were imprisoned or executed by forces loyal to Spain. At first the rebels disputed the legitimacy of the French-installed Joseph Bonaparte while recognizing the sovereignty of Ferdinand VII over Spain and its colonies, but later the leaders took more radical positions, rejecting the Spanish claim and espousing a new social order including the abolition of slavery. Secular priest José María Morelos called the separatist provinces to form the Congress of Chilpancingo, which gave the insurgency its own legal framework. After the defeat of Morelos, the movement survived as a guerrilla war under the leadership of Vicente Guerrero. By 1820, the few rebel groups survived most notably in the Sierra Madre del Sur and Veracruz.