What was mission san Fernando rey built of?

Mission San Fernando Rey de Espana was built primarily using adobe bricks, a construction material made from a mixture of clay, sand, straw, and water. Adobe bricks were common in Spanish colonial architecture due to their availability, affordability, and ability to provide insulation against extreme temperatures. The mission's walls, structures, and fortifications were constructed using these adobe bricks, which were sun-dried to harden and create durable building materials.