Late in the war for the independence of the United States, Spain joined France and this country in their contest with British power. The Spanish commandant of St. Louis sent a. company across the Illinois prairies to attack a British post beyond Lake Michigan; a larger force from New Orleans occupied the district of Baton Rouge and other western regions of British West Florida, and in March 1781 the governor of Spanish Louisiana came by land and sea and laid siege to British Pensacola.
"British and Spanish Fortifications of Pensacola, 1781-1821,"
Florida Historical Quarterly: Vol. 20
, Article 5.
Available at: https://stars.library.ucf.edu/fhq/vol20/iss3/5