Alexandre de Gusmão

Alexandre de Gusmão (Santos, 1695 - Lisbon, 1753) was a diplomat born in the Portuguese colony of Brazil. He is regarded as one of the best diplomats of his time, chiefly for his role in negotiating the Treaty of Madrid in 1750 (revoked in 1761), when Portugal and Spain were attempting to delimit their territorial possessions in South America and Asia. Born in the city of Santos, he may be considered one of the precursors of the application of the principles of Illuminism to international relations, adopting the principle of uti possidetis, according to which each state has the right to the land that it actually occupies, as well as the idea of "natural boundaries", which suggests the use of prominent geographical accidents – such as rivers and mountain ranges – to set the limits between states. He graduated in Law and was the representative of Portugal to various states, among which Rome, where he came to be invited to join Pope Innocent XIII's court. He was also a brother of Bartolomeu de Gusmão, a priest and naturalist recalled for his early work on lighter-than-air airship design (balloons).