Official correspondence

Among several papers left by Félix de Azara in the possession of his companion and friend, Don Pedro Cerviño, was the autograph draft of his Official correspondence unpublished on the work of demarcation: important document, containing the history of the controversies raised by the Portuguese Commissioners, with several observations on the treaty of 1777.
The official correspondence had enormous value in the negotiations between the Spanish and the Portuguese of those times for the colonial territories. In this Correspondences the errors of the negotiators are pointed out;

• especially that of passing the demarcation line through two rivers (Ygurey and Corrientes), which were not where the negotiators had placed them.
• After many investigations Azara located, the first in the Yaguarey, or Igurey de d’Anville, and the second in the Appa River.

This official correspondence thus allowed to reorder disputed territories reasonedly, pacifying and consolidating the emergence of future Latin American countries.