In 1736 Diego de Espinosa owned a cattle ranch on Diego Plains, a flat, open area east of here. For protection against Indians, his house was surrounded by a 15-foot-high palisade with two bastions at opposite corners. Later manned by Spanish soldiers, this post became known as Fort San Diego. On May 23, 1740, during the British expedition against St. Augustine, General James Oglethorpe’s 400-man army captured the fort and its 50 defenders. The British added a ditch and breastwork and used the fort to protect the St. Johns River–St. Augustine supply line. They evacuated it on July 25, and by 1743 it lay in ruins.
