The last two decades of the seventeenth century were critical years in determining the eighteenth-century destiny of the entire breadth of the Spanish borderlands in North America. Overshadowing the outcome of the international rivalry over the continent were three changing tenets in international law during the last third of the seventeenth century. The first was Spain’s acceptance of “freedom of the seas” in place of mare clausum (closed sea) whereby she had sought exclusivism of the waters adjacent to its territorial holdings. Another changing tenet, to Spain’s advantage, was the European abandonment of “no peace beyond the line” (of demarcation) whereby aggressive acts committed in America would have no effect on peaceful relations among the European powers. Privateers had used this tenet to their advantage, as well as had Spain’s rivals in Europe, and would continue to do so into the early eighteenth century. The third, and most significant change, was Spain’s acceptance of a new tenet, uti possidetis (as you now possess), whereby “effective occupation alone gives valid title to colonial lands and the rights acquired by prior discovery are only effective if they are followed up by settlement.“ Formalized by treaties, the most important was the Treaty of Madrid, signed in 1670. Under it Spain recognized the English settlements in America on the condition that they would not engage in contraband trade with the Spanish dependencies. The boundary between English Carolina and the Spanish Florida provinces was fixed on a line running due west from a point in Port Royal Sound approximately sixty miles south of Charleston. By this time England and France posed the major threats to the former Spanish exclusivism, but England would prove to be the most successful in adjusting to this new tenet.
Gillaspie, William R.
"Survival of a Frontier Presidio: St. Augustine and the Subsidy and Private Contract Systems, 1680-1702,"
Florida Historical Quarterly: Vol. 62:
3, Article 3.
Available at: https://stars.library.ucf.edu/fhq/vol62/iss3/3