The book was written by a Franciscan missionary, Fray Felix Huerta OFM chronicling the history and 19th century status of the mission territories belonging to the Franciscan province of San Gregorio Magno. Included in his account are history of the Franciscan administered towns in Bulacan, Laguna, Tayabas (Quezon), and Bicol. Thus, this a valuable primary source for local histories of the said territories. For the eminent propagandist Trinidad Pardo de Tavera in his Biblioteca Filipina, this work of Fray Huerta “es un libro importantisimo lleno de datos relativos a historia de Filipinas, que es indespensable consultar para saber detalles de los pueblos admintrados por los franciscanos. (It is a very important book full of data related to the history of the Philippines, which is essential to consult to know details of the towns administered by the Franciscans.)” (Lars Raymund C. Ubaldo, Ph.D.)