Emil Oblasser studied for the Franciscan priesthood (taking the name of Bonaventure) at Mission Santa Barbara from 1901 until 1908. His missionary work in Arizona resulted in the construction of over a dozen schools and churches on what would become known as the Papago Indian Reservation in southern Arizona. He was a member of the Committee that contributed to the formation of the reservation (1915), and he was a key advisor in both the legal battle against the Hunter Heirs in their claim to Papago Lands (1926) and in the formation of the tribal constitution (1936). During his tenure, he gathered unique information on the Franciscan influence in Pimeria Alta, and collected censuses and other ethnological data on Indian populations. In the course of his research, he built a collection of books on the region which are now housed in the Oblasser Library at Mission San Xavier.

Collection consists of photocopies of chiefly correspondence, 1908-1950, of Franciscan missionary and historian Father Bonaventure Oblasser, O.F.M. during his appointments, mainly to the Papago Indians (now known as Tohono O'odham), in Arizona. Included also are photographs that consist of images created by various Franciscan friars of the Saint Barbara Providence of the Order of Franciscan Friars depicting scenes from various Indian reservations in Arizona and Southern California. This collection also includes papers of Franciscan missionary, Nicholas Perschl (1887-1969), relating to his missionary work to the Papago Indians.