The article presents an analysis of the letter titled "Exhorto a la obediencia del rey," written by Franciscan friar Cirilo Alameda y Brea in 1820, in order to discuss the position of the Franciscan order towards the Independence of Mexico at the beginning of the 19th century. Particular focus is given to the Franciscan educational institution Colegio Real y Pontificio de la Purísima Concepción de Celaya, located in Celaya, Mexico. Topics discussed include the political context of Cádiz, Spain, particularly the Cádiz Constitution of 1812, the historical role of king Fernando VII, and politics in Nueva España or New Spain, now modern day Mexico. A transcription of the document is also included.