In subsequent years, the insurgency was near collapse, but in 1820 Viceroy Juan Ruiz de Apodaca sent an army under the criollo general Agustín de Iturbide against the troops of Vicente Guerrero who had among his trusted soldiers, Filipino Mexicans who were concentrated in Guerrero, a state later named after Vicente Guerrero himself and where the Mexican flag was first sewn. Chief among the Filipino-Mexican soldiers was General Isidoro Montes de Oca who defeated Royalist armies 3 times his force's size. Filipino participation occurred even earlier when Manila-born Ramón Fabié joined the insurgents. Then, the Criollo Royalist, Agustin Iturbide, instead of attacking Vicente Guerrero, approached Guerrero to join forces as he was impressed with his tenacity despite fighting larger odds, and on 24 August 1821 representatives of the Spanish Crown and Iturbide signed the "Treaty of Córdoba" and the "Declaration of Independence of the Mexican Empire", which recognized the independence of Mexico under the terms of the "Plan of Iguala". Similarly to José María Morelos' goals. A provision of the Plan of Iguala of Agustín de Iturbide bringing about Mexican independence in 1821, also included Catholic exclusivity in the religious sphere. The Constitution of 1824 declared that the official religion of the Republic would be Catholic.