Maritime history of Florida
Spain ceded Florida to the United States as part of the Adams–Onís Treaty of 1819, and Florida became a U.S. territory in 1821. Coastal trade with other markets continued to expand and towns like Jacksonville, Pensacola and Tampa became important ports. After becoming a U.S. territory, the federal government began building a series of lighthouses as aids to navigation along the coasts of Florida to mark dangerous headlands, shoals, bars and reefs.
Fugitive slaves in the United States
Prior to the establishment of the United States, and extending until Florida became a territory of the United States in 1821, the destination of many fugitive slaves was Spanish Florida. In a policy formalized in 1693, Spain offered escaped British slaves safe refuge and freedom, provided they converted to Catholicism and served a period in the militia. The first free settlement of former slaves in the Americas was Santa Teresa de Mosé, near St. Augustine, Florida. This community disbanded when Florida became a British possession in 1763, most of the slaves withdrawing to Cuba with the Spanish troops defending the San Marcos fort in Saint Augustine.