Founding the missions in California required a combination of planning, hard work, and luck. Both church and government officials in Mexico City made extensive preparation for each new mission to be founded in this remote region. When they got to California, mission founders followed the plans as much as possible but often faced unforeseen challenges. In the end, they learned to improvise.

The California missions were built by order of the viceroy. The viceroy was the king's highest permanent official in New Spain, as the colony that stretched from Panama to California was then known. Missionaries and other church officials might try to influence the viceroy, but ordering construction of a new mission was a government decision. Missionaries needed the viceroy's approval for many matters relating to the missions. He had to approve the site chosen for a mission, all building projects, and even...