Our view of the Spanish missionary Church results from the convergence of two streams of historical writing. The first uses the activities of a particular religious order or its most illustrious members to frame the foundation and growth of a missionary enterprise. The second pursues a thematic approach, emphasizing the importance of the missions as foci of Spanish culture in a native world. Within this second stream falls the particularly North American interest in the frontier with its stress on the mission stations as the vanguard of Iberian religious, political, and social institutions.Though widely divergent in organization and emphasis, both streams present a picture of isolation. Solitary missions existed as self-contained theocracies on the very edge of the viceroyalty. The missionaries themselves constantly stressed this view. Their correspondence cites the difficulties of operating stations at great remove from the seats of Spanish power in America. Professional historians, following the diaries and letters of the missionary fathers, have placed priests, neophytes, and — in North America — presidial soldiers beyond the aid or control of metropolitan authority touched only by an occasionalvisitaor supply train.