ABSTRACT The University of Talca's Centro de Documentación Patrimonial (Centre of Documental Heritage), near the city of Chillán (Ñuble-Chile Region), preserves an unpublished music sources attesting the musical activity carried out by the Franciscan community hosted, mainly during the 19th century, at the missionary School of Chillán. This article provides a description of this material as well as the historical background and practices in which music was performed, having into consideration also some codicological and liturgical features of the most relevant primary sources.