The presidios are a very important part of the mission. The Spanish built presidios to protect the coast from foreign troops. Spain established presidios so the soldiers had a place to stay near the missions in case they needed help or was under attack. The soldiers also helped with the Indians if they tried to run away.The troops or soldiers lived in presidios (forts) near the mission. Presidios could hold 4-7 soldiers as there living quarters. They were set aside from missions about 1 to a half mile away. If it weren't for presidios soldiers may not have been able to watch over and protect the missions and the Indians may not have cooperated.