Fearing to lose Cabinda, Portugal had the Chinfuma and Chicamba agreements signed with the indigenous Cabindan chiefs between 1883 and 1884, then on February 1, 1885, the Treaty of Simulambuco. This document thus allows Portugal to have a legal basis on Cabinda with a view to the definitive delimitation of African territories during the Berlin Conference of 1885, a meeting of European powers for the sharing of colonies and areas of influence in Africa.

The most important of these treaties is that signed on February 1, 1885 in Simulambuco by the King of Cabinda, Ibiala Mamboma, who placed Cabinda under the protectorate of the Kingdom of Portugal. The validity of this treaty was recognized by the Berlin conference, because the British and the Germans understood the interest in dividing the region of the mouth of the Congo river between their three rivals, French, Belgians and Portuguese.

Today, this protectorate treaty constitutes the founding act of the separatists, insofar as it legally establishes the existence of a Cabindan political entity. For indeed, the end of the protectorate should have been accompanied by the independence of Cabindian territory, recognized by international law.

All the more, the Portuguese constitution of 1933 in force until 1975, establishes a clear and clear distinction between Angola and Cabinda, as two territories, in particular in its article 1, paragraph 2 – title 1.

In 1957, Portugal placed Cabinda and Angola under the authority of a single administrator, without modifying the Treaty of Simulambuco, and in contradiction with the Portuguese constitution, which distinguished these two territories. Seeming to endorse this de facto merger, United Nations General Assembly resolution 1542 (XV) adopted on December 15, 1960 relating to decolonization, retained “Angola including the enclave of Cabinda”. But, in 1964, after a meeting in Cairo, the Organization of African Unity (OAU) published a list of countries to be decolonized, separately mentioning Angola (case n° 35) and Cabinda (case n° 39 ). This did not happen, the discovery of large offshore oil fields in 1966 not prompting Portugal to abandon this territory.

On January 15, 1975, article 3 of the final act of the Alvor Conference, signed by the three Angolan separatist politico-military movements (MPLA, FNLA, UNITA) and Portugal, proclaimed the attachment of Cabinda to the ‘Angola. The FLEC was not invited. Nevertheless, it should be remembered that these same Alvor agreements were suspended by Portugal a month and seventeen days before the proclamation of the independence of Angola. The Cabindan separatists rightly consider the Alvor agreements void.