This dissertation adds fresh insights into the creation of popular religion in colonial Mexico, beginning in the most neglected time period -- the seventeenth century -- and by conducting original research on the most neglected religious authorities of the Catholic Church: the secular clergy. I draw from diverse manuscript and print sources gathered from more than thirty archives in Mexico, Spain, the United States, Chile, Germany and England to trace a continuous thread of Oratorian identity across a dynamic set of institutional cultures in Mexico City. Oratorians worked along the cultural and spatial borderlands of colonial Mexico City, experimenting with innovative and controversial forms of Catholic ritual and adapting a religious cultu...