 Fortifications built here by the Spanish in the 17th century, and rebuilt several times, provided the venue for force of arms repeatedly up through the American Civil War.In the best-known incident, Andrew Jackson, in his cavalier incursion into Spanish Florida in 1818, executed British nationals Robert Chrystie Ambrister and Alexander George Arbuthnot at the old fort, as well as Native American leader Francis the Prophet.This nearly embroiled the United States in international strife.