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.
Alta California
Mexico gained independence from Spain in 1821 upon conclusion of the decade-long Mexican War of Independence (not acknowledged by Spain until 1836). As the successor state to the Viceroyalty of New Spain, Mexico automatically included the provinces of Alta California and Baja California as territories. Alta California declared allegiance to the new Mexican nation and elected a representative to be sent to Mexico. On November 9, 1822, the first legislature of California was created. With the establishment of a republican government in 1824, Alta California, like many northern territories, was not recognized as one of the constituent States of Mexico because of its small population. The 1824 Constitution of Mexico refers to Alta California as a "territory".