'PATRONATO SAN XAVIER is a nonsectarian, nonprofit corporation that began in June, 1978. The corporation is ''to be used solely and exclusively for historical, research, scientific and education purposes concerned with the restoration, maintenance and preservation of Mission San Xavier del Bac near Tucson, Arizona.'' Patronato San Xavier grew out of the recognition that the fabric of this National Historic Landmark was badly in need of repair, refurbishing, and maintenance. The work was beyond the financial abilities, expertise, and vocation of the Franciscan friars responsible for administration of the daily affairs of the church, the heart of an active parish whose members are the Tohono O'odham (formerly Papago Indians) residents of the San Xavier District of the Tohono O'odham Nation. The Franciscans, who operate a parochial elementary school on the reservation, are understandably more concerned with people than with historic structures. Moreover, because Mission San Xavier is an active church, public funds could not be used in its care.'