C
"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.[51] President James Monroe was authorized on March 3, 1821 to take possession of East Florida and West Florida for the United States and provide for initial governance.[52] Andrew Jackson, on behalf of the U.S. federal government, served as a military commissioner with the powers of governor of the newly acquired territory for a brief period.[53] On March 30, 1822, the U.S. Congress merged East Florida and part of West Florida into the Florida Territory.[54] "