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.
Mexico
Agustín de Iturbide became constitutional emperor of the First Mexican Empire in 1822. A revolt against him in 1823 established the United Mexican States. In 1824, a Republican Constitution was drafted and Guadalupe Victoria became the first president of the newly born country. Central America, including Chiapas, left the union. In 1829 president Guerrero abolished slavery. The first decades of the post-independence period were marked by economic instability, which led to the Pastry War in 1836. There was constant strife between Liberals, supporters of a federal form of government, and Conservatives, who proposed a hierarchical form of government.