Spheres of influence

Demarcation of British and Portuguese spheres of influence along the Zambesi, from: Délimitation des sphères d’influence du Portugal et de la Grande-Bretagne dans l’Afrique orientale depuis le parallèle de 18? 30’ S. jusqu’au confluent du Save et du Lunde: conclusions. Florence : Établissement Typographique Florentin, 1896 [FCDO Historical Collection FOL. DT36.5 MEM]In June 1891 Great Britain and Portugal signed a treaty to ‘settle definitively the boundaries of their respective spheres of influence in Africa’ i.e. central and southern Africa. Among other points, they agreed that ‘one power will not, in the sphere of the other, make acquisitions, conclude treaties, or accept sovereign rights or Protectorates’.

However, when the boundaries were defined in the treaty, the two parties seem to have had only a vague and imperfect knowledge of the actual topography and the configuration of the territory in Africa. In addition, they did not seem to have had an accurate map.

So when a year later the commissioners of the two governments tried to trace the boundary line to the south of the Zambezi River in situ (the border between the present-day countries of Zimbabwe and Mozambique) according to the treaty, several disagreements ensued about what was actually meant by some of the geographical terms used in the treaty, as well as how these terms related to the actual territory in the Manica plateau.

In order to settle these disagreements and to establish the boundaries of their respective spheres of influence, the two parties referred to an arbitrator, namely Paul-Honoré Vigliani, former chief president of the Court of Cassation of Florence and minister of state of the Kingdom of Italy. Whereas the original treaty had been written in English and Portuguese, which had caused some of the disagreements due to the imprecise translation of certain words, the parties agreed that the documents relating to the arbitration should be drawn up in French.

During the arbitration, each party submitted several documents in order to prove their case. On display is a collection of the individual documents submitted by the two parties, together with the final decision by the arbitrator. The case was finally settled in January 1897. The two diagrams show the Manica plateau boundary line to be adopted, according to the Portuguese. The difference between the two diagrams lies in the fact that the actual position of the 33? meridian in relation to the territory had not been fully established.

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