British settlement on St. Simons Island began in 1736 when General James Edward Oglethorpe established the fortified town of Frederica seven miles northwest of today's lighthouse. Fort Frederica defended against the Spanish in Florida and protected the British ports of Savannah and Charleston. Oglethorpe also built Fort St. Simons on the south end of the island to prevent enemy warships from attacking Fort Frederica, and about 350 soldiers were garrisoned in nearby barracks. When conflict between Great Britain and Spain intensified in 1740, Oglethorpe laid siege to Castillo de San Marcos at St. Augustine, Florida, in June and July with little success. The Spanish retaliated two years later by attacking St. Simons Island. On July 7, the British engaged and defeated a Spanish scouting party near Fort Frederica, and the Spanish fled south to Fort St. Simons with Oglethorpe and his troops in pursuit. These troops ambushed and again defeated the Spanish in a skirmish that became known as the Battle of Bloody Marsh. Fearing the arrival of British warships from Charleston, the Spanish destroyed Fort St. Simons before sailing back to Florida on July 15, never to return. When the war with Spain ended in 1748, British troops withdrew from St. Simons Island. The exact location of Fort St. Simons has not been determined; eighteenth-century maps indicate that the fort and barracks were near today's lighthouse, but shoreline erosion has probably erased the physical record.