- Military Support: The missions were established under California rule and received military support the from Spanish military, most notably the Presidios, which played a crucial role in protecting the missions and their inhabitants from outside threats and indigenous attacks.
- Disease Immunity: The indigenous population in California was largely not immune to European diseases, which led to a dramatic population decline. The missions provided some protection against these diseases and helped preserve the indigenous population in some regions.
- Education and Conversion: The Spanish missions were successful in converting many indigenous peoples to Catholicism. Through their educational efforts and religious teachings, they were able to spread their religious ideologies and cultural practices.
- Economic Stability: The missions created a stable economic system based on agriculture, livestock raising and trade. Missionaries introduced new agricultural techniques and crops, leading to increased food production and sustaining large communities.
- Indigenous Cooperation: In some cases, indigenous leaders choose to cooperate with Spanish missionaries due to the mutual benefits of trade, protection, and other alliances. These partnerships contributed to the success and longevity of several missions.
- Adaptation and Resilience: Over time, the missions adapted to the local environment and circumstances. They developed new methods of agriculture, adopted some indigenous practices and technologies, and gradually integrated into the social and economic fabric of California.
- Spanish Persistence and Exploration: The Spanish were determined to establish a presence in California, even in the face of challenges and setbacks. Their expeditions, exploration, and resourcefulness aided in the establishment and sustainment of the mission system.