History of Florida
In 1810, parts of West Florida were annexed by proclamation of President James Madison, who claimed the region as part of the Louisiana Purchase. These parts were incorporated into the newly formed Territory of Orleans. The U.S. annexed the Mobile District of West Florida to the Mississippi Territory in 1812. Spain continued to dispute the area, though the United States gradually increased the area it occupied.Seminole Indians based in East Florida had been raiding Georgia settlements, and runaway American slaves were their allies; Negro Fort, an abandoned British fortification in the far west of the territory, was manned by both Indians and blacks. The United States Army would lead increasingly frequent incursions into Spanish territory, including the 1817–1818 campaign against the Seminole Indians by Andrew Jackson that became known later as the First Seminole War. The United States now effectively controlled East Florida. Control was necessary, according to Secretary of State John Quincy Adams, because Florida had become "a derelict open to the occupancy of every enemy, civilized or savage, of the United States, and serving no other earthly purpose than as a post of annoyance to them." Florida had become a burden to Spain, which could not afford to send settlers or garrisons. Madrid therefore decided to cede the territory to the United States through the Adams–Onís Treaty, which took effect in 1821.
Republic of West Florida
The United States did not recognize the independence of the Republic of West Florida, and on October 27, 1810, President James Madison of it, on the basis that it was part of the Louisiana Purchase. In his proclamation, Madison invoked the portion of the Louisiana Purchase agreement that directly quoted the 1800 St. Ildefonso treaty between France and Spain: Louisiana, Madison stated, had "the same extent that it had in the hands of Spain, and that it had when France originally possessed it." However, neither the 1800 treaty nor the 1803 purchase includes the word "originally"; instead, they state, "with the same extent that it now has in the hands of Spain and that it had when France possessed it." Madison's tweak served his annexation rationale but had no basis in the treaty language.