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–Republic of Texas relations
Republic of Texas–Mexico relations refers to the historical foreign relations between the Republic of Texas and Mexico. Relations were unofficially initiated in 1836 at the signing of the Treaties of Velasco, which de facto declared Texas independent from Mexico, though the Mexican Government never fully recognized Texas' Independence. The relations between the two countries, however hostile, continued until 1845 after the annexation of Texas by the United States, and the beginning of the Mexican–American War.