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.
Guatemala–Mexico relations
Guatemala and Mexico are two neighboring countries who share a common cultural history from the Maya civilization and both nations were colonized by the Spanish empire. In 1821, Mexico gained independence from Spain and administered Guatemala (and most of Central America) during the First Mexican Empire. In 1823, the empire collapsed and Guatemala joined the United Provinces of Central America, however, the Guatemalan region of Chiapas choose to separate from Guatemala and joined Mexico as a state. In 1838 the union dissolved and Guatemala became an independent nation. Both nations established diplomatic relations in 1838 and diplomatic missions were soon opened. In 1926 both nations resident diplomatic missions were elevated to embassies.