On October 27, 1795, at the summer residence of the Spanish court in the village of San Lorenzo del Escorial, near the Sierra de Guadarrama range, one of the most widely discussed events in history took place—the signing of the Treaty of San Lorenzo. It was an event the importance of which can only be compared with that of 1783 in the history of the United States, that recognized it before the world as a nation free, independent, and sovereign. After fifteen years of continued diplomatic overtures and controversy between Spain and the United States over the southern boundary and the navigation of the Mississippi River, Spain’s acquiescence to the United States opened the greatest of possibilities for her future development, and marked the beginning of the end of Spain’s expansion. The importance of the treaty and the astounding fact of its realization have brought into being many critical and historical works, but only a few of these writers have had direct access to original sources. Accordingly, with the perspective that time affords, and basing my observations principally on original documents conserved in the National Historical Archives, Madrid, I should like to present yet another interpretation of the conditions which preceded the signing of the Treaty of San Lorenzo. A detailed background of the question can be found in my: “Los Antecedentes Políticos y Diplomáticos del Tratado de Pinckney.”
The powers of Thomas Pinckney that designated him as “envoy extraordinary and only commissioned plenipotentiary” authorized him to negotiate and sign, subject to the ratification of the President and the consent of the Senate, a treaty or treaties “concerning the navigation of the Mississippi River and other matters such as the confines and territories of the United States and His Catholic Majesty”; he also was empowered to conclude, in the same way, an agreement “of general commerce between the United States and the kingdoms and dominions of His Catholic Majesty.”
