Luis de Onís y González Vara López y Gómez (1762–1827) was minister plenipotentiary of the Supreme Junta of Spain to the United States. He joined the Spanish Ministry of State in 1798 and helped negotiate the short-lived peace treaty of Amiens with France in 1802. Onís reached New York on 4 Oct. 1809 and had recently arrived in Washington, but due to doubts whether his British-backed government or its Napoleonic rival was actually in control in Spain, compounded by indiscretions of his own serious enough that James Madison later complained of them in a confidential message to Congress, Onís was not officially recognized as minister until 1815. His American tour of duty culminated in the Adams-Onís Treaty of 1819, under which the United States acquired Florida and the boundaries between the remaining Spanish possessions in North America and the United States were established. Onís subsequently represented Spain as ambassador to Great Britain (Angel del Rió, La Misión de Don Luis de Onís en los Estados Unidos [1809–1819] [1981], 193–208; Madison, Papers description begins William T. Hutchinson, Robert A. Rutland, John C. A. Stagg, and others, eds., The Papers of James Madison, 1962– , 31 vols.: Congress. Ser., 17 vols.; Pres. Ser., 5 vols.; Sec. of State Ser., 6 vols description ends , Pres. Ser., 3:108; Onís, Memoria Sobre las Negociaciones entre España y los Estados Unidos de América [1820; repr. ed. Jack D. L. Holmes, 1969], xv–xxix).