Americans and runaway slaves from the Southern colonies to move to their territory. The Spanish hoped that the increased number of inhabitants of Spanish Florida would be effective in case of potential raids by American colonists. As early as 1689, enslaved Africans fled from the South Carolina Lowcountry to Spanish Florida seeking freedom. These were people who gradually formed what has become known as the Gullah culture of the coastal Southeast. Under an edict from King Charles II of Spain in 1693, the black fugitives received liberty in exchange for defending the Spanish settlers at St. Augustine. The Spanish organized the black volunteers into a militia; their settlement at Fort Mosé, founded in 1738, was the first legally sanctioned free black town in North America. Not all the slaves escaping south found military service in St. Augustine to their liking. More escaped slaves sought refuge in wilderness areas in northern Florida, where their knowledge of tropical agriculture—and resistance to tropical diseases—served them well. Most of the black people who pioneered Florida were Gullah people who escaped from the rice plantations of South Carolina (and later Georgia). As Gullah, they had developed an Afro-English based Creole, along with cultural practices and African leadership structure. The Gullah pioneers built their own settlements based on rice and corn agriculture. They became allies of Creek and other Native Americans escaping into Florida from the Southeast at the same time. In Florida, they developed the Afro-Seminole Creole, which they spoke with the growing Seminole tribe. Following the Treaty of Paris signed in 1763 at the conclusion of the Seven Years' War, Spanish Florida was ceded to the Kingdom of Great Britain. The area remained a sanctuary for fugitive slaves from the Southern colonies, as it was lightly settled. Many slaves sought refuge near growing Native American settlements. In 1773, when the American naturalist William Bartram visited the area, he referred to the Seminole as a distinct people, their name apparently coming from the word "simanó-li", which according to John Reed Swanton, "is applied by the Creeks to people who remove from populous towns and live by themselves.". William C. Sturtevant says the ethnonym was borrowed by Muskogee from the Spanish word cimarrón, supposedly the source as well of the English word maroon used to describe the runaway slave communities of Florida and of the Great Dismal Swamp on the border of Virginia and North Carolina,