The Berlin West Africa Conference, convened by Bismarck and sitting from November 1884 to February 1885, brought fourteen states together to settle rival claims in the Congo basin. Its General Act declared the Congo basin neutral, guaranteed free trade and navigation on the Congo and the Niger, prohibited the slave trade in the region, and set out the conditions on which European claims to African coasts would be recognised. Britannica records that although colonisation had already begun, its pace greatly accelerated after the conference. The partition that followed was carried out by treaty with African rulers, by concession company, and by military conquest - against the Asante, the Sokoto Caliphate, the Mahdist state in Sudan, the Ndebele, Dahomey, Samori Ture's empire and many others - and left almost the whole continent under European claim by 1900. The conference is often described as having divided Africa; more precisely, it set the rules by which the powers agreed to recognise each other's divisions.
European powers partitioned almost the entire African continent among themselves, formalising the rules of claim at the Berlin Conference of 1884-85
There was no census of most of Africa in this period. McEvedy and Jones' regional series and the demographic reconstructions used by Frankema and Jerven put the continent at roughly 120-140 million around 1900. The partition acted on essentially the whole continent: by 1900 only Ethiopia and Liberia remained outside European rule.
There is no aggregate toll for the partition. Deaths occurred in the conquest campaigns and in the labour and taxation regimes that followed, and the largest of these - the Congo Free State rubber regime, the French Algerian and Saharan campaigns, the Sudan campaigns, and after 1900 the German suppression of the Herero and Nama - are counted separately where the evidence allows. Aggregating them here would double-count and would imply a precision the sources do not support.
Dem. Rep. Congo