Toward the end of the 17th century, as the Spanish pondered the fate of their North American holdings, they did not want to see a repeat of the Jamaican situation. Spain had founded the first European settlement in North America, at St. Augustine in 1565, but by the 1690s, Spanish power was in the midst of a long, steady decline. After 140 years, St. Augustine was still just a distant outpost of empire. Florida as a whole was thinly populated, poorly defended, and extremely vulnerable to British attack. The English colonies, meanwhile, were growing vigorously, thanks in large measure to a dramatic increase in the importation of African slaves.
When Spaniards looked north and saw the English slaves, they saw a strategic opportunity.
Twyman 28, Weber 89-91, Sturtevant "Creek" 100.