Jus gentium e diritto di legazione in età moderna: gli Stati terzi e la securitas dei legati in transito

A fundamental institute of jus gentium, diplomatic law constituted a tool for interstate relations in the modern age. It enabled states to recognize each other, legitimize each other, maintain stable contacts and regulate their relations. The smooth functioning of legations was guaranteed by the diplomatic prerogatives that arose from the close diplomatic relationship between the sending and receiving sovereigns. However, based on the strictly bilateral matrix of this relationship, one may ask whether diplomats in transit across third countries could benefit from the protection of the law of nations. The study of the Rincón-Fregoso case (1541) allows us to approach the issue from the inside and to understand what the positions of the doctrine of the modern age were on the point. It is worth noting that the harmless transit hypothesis put forward in 1758 by Vattel presented original and interesting insights.