The area known as West Florida was originally claimed by Spain as part of La Florida, which included most of what is now the southeastern United States. Spain made several attempts to conquer and colonize the area, notably including Tristán de Luna's short-lived settlement in 1559, but it was not settled permanently until the 17th century, with the establishment of missions to the Apalachee. In 1698 the settlement of Pensacola was established to check French expansion into the area.
Beginning in the late 17th century, the French established settlements along the Gulf Coast and in the region as part of their colonial La Louisiane, including Mobile (1702) and Fort Toulouse (1717) in present-day Alabama:134 and Fort Maurepas (1699) in present-day coastal Mississippi. After years of contention between France and Spain, they agreed to use the Perdido River (the modern border between Florida and Alabama) as the boundary between French Louisiana and Spanish Florida.:122
Before 1762 France had owned and administered the land west of the Perdido River as part of La Louisiane. A secret treaty in 1762 had effectively, upon being revealed in 1764, ceded to Spain all of French Louisiana west of the Mississippi River, as well as the Isle of Orleans. Notably, Spain failed to make good by occupancy its title to Louisiana until 1769, when it took formal possession. For six years, therefore, Louisiana as France possessed it, and as Spain received it, included none of the West Florida territory between the Mississippi and Perdido rivers, as the title to that territory passed immediately from France to Britain in 1763, following its defeat in the Seven Years' War.:48
Under the treaty concluding the French and Indian War (Seven Years' War) in 1763, Britain obtained immediate title to all of French Louisiana east of the Mississippi River. This included the land between the Perdido and Mississippi rivers. Spain also ceded to Great Britain its territory of La Florida, in exchange for Cuba, which the British had captured during the war. As a result, for the next two decades, the British controlled nearly all of the coast of the Gulf of Mexico east of the Mississippi River.:134 Most of the Spanish population left Florida at that time, and its colonial government records were relocated to Havana, Cuba.