Castillo de San Marcos - Second Spanish Period

Second Spanish Period

When Spain regained control over Florida they found a much changed territory. Many Spaniards had left Florida after the hand over to Britain, and many British citizens stayed after the hand over back to Spain. Many border problems arose between Spanish Florida and the new United States. Spain changed the name of the fort back to the Castillo de San Marcos, and continued to build upon the improvements that Britain had made to the fort in an effort to strengthen Spain’s hold on the territory. However, due to increased pressure from the United States and several other factors, in 1819, Spain signed the Adams-Onís Treaty, ceding Florida to the United States, which was transferred in 1821.