March 12 1812: Patriot's War

On March 12, 1812, General George Mathews led a private army of Georgians, who called themselves “Patriots”, across the St. Mary’s River to take control of East Florida. The area was  still administered by Spain. Matthew's forces met opposition from the local population including the Seminoles and their African American allies who sided with Spain. Matthews was probably acting with the tacit support of the Madison administration.


American public opinion, however, was soon to oppose the invasion. As a consequence, Madison withdrew official support but Matthew's "Patriots" remained in East Florida for two years. East Florida eventually became part of the United States when an American army under Andrew Jackson invaded East Florida during the First Seminole War in 1818. Spain formally ceded all of its Florida territory to the United States under the Adams-Onís Treaty in 1819. As part of the treaty, the U.S. also agreed that it would make any claims on Texas and agreed to pay $5 million. 

The United States had acquired West Florida. The Louisiana Purchase with France in 1803 had been unclear as to the exact boundaries of what previously had been Spanish possessions. The United States claimed the territory from the Perdido River to the Mississippi River. Spain claimed that this area was part of their province of West Florida and not part of Spanish province of Louisiana acquired by the United States. Negotiations between the two countries went nowhere but American settlers created facts on the grounds by moving into the area. On September 23, 1810, a rebellion led to the establishment of the Republic of West Florida which lasted for ninety days until October 27, 1810 when the new republic was annexed by the bigger republic by proclamation of President James Madison.