Complex sentence: Also built on Matagorda Bay near La Salle's Fort Saint Louis, the mission and complementing Presidio La Bahia (fort) was intended to secure the Texas coastline from the French and to gather the local Indians.
Split into simpler sentences: Also built on Matagorda Bay near La Salle's Fort Saint Louis. The mission and complementing Presidio La Bahia (fort) was intended to secure the Texas coastline from the French and to gather the local Indians.