Agustin de Iturbide was a Royalist officer in the Mexican War of Independence who fought the insurgent leader Vicente Guerrero. Failing to defeat the insurgency, Iturbide adopted the cause of independence and allied with Guerrero (an event known as the "Embrace of Acatempan"), thereby making it possible to end the war and secure independence from Spain. On February 24, 1821, Iturbide proclaimed the Plan of Iguala (named for a city in the present state of Guerrero, in the south of the country), and with it declared the independence of the then-called América Septentrional (Mexico). After the proclamation of independence he continued with the creation of "Imperial Mexico." His army was called that of the Three Guarantees: Catholicism, Independence, and Union (of the opposed parties after the war). The independence of Mexico was consummated after Iturbide entered Mexico City at the head of his troops on September 27, 1821.