The Belgians and French overcame the obstacle of the rapids above the Congo mouth by building railways from seaports at Matadi and Pointe Noire. Leopoldville (Leo) and Brazzaville (Brazza) became the twin focal points of the river trade of the Congo basin, as well as administrative capitals.
Portugal, although giving up its historic claim to the Congo mouth, kept the Cabinda enclave, as well as the Angolan south side of the estuary. The new frontiers divided up the once powerful (Ba-)Kongo people (22), whose old capital was at São Salvador. They now number about 3 million, half in Portuguese territory; about 800,000 in ex-Belgian Congo, in and south of ' Leo' (plus other (Ki-)Kongo-speaking associated tribes); the rest in ex-French Congo, where they dominate ' Brazza'. Each section of the Bakongo has naturally been affected by the fate of the others. When the French Congo gained self-government within the French Community in 1958 (14, 16) under Abbé Foulbert Youlou (now president), the Bakongo of Leo, led by Kasavubu, followed events across the river keenly. Kasavubu and Youlou worked closely together at times. In 1961 the risings in northern Angola and Cabinda (34) were, similarly, set off by events in, and supported from, the ex- Belgian and ex-French Congos.
Kasavubu's party, the Abako, organized passive resistance in the lower Congo in 1959 so successfully that Belgium virtually lost control of the area; this precipitated the events of 1960. But Kasavubu, although first president of the (ex-Belgian) Congo republic, had earlier sought not only independence but also reunion of all the Bakongo -- possibly involving secession from the republic.
Leo, however, is not a Bakongo city. Much of its population (now around 400,000) has been drawn in from distant areas, notably from the region, upstream in Equateur province, of the (Ba-)Ngala peoples (Lingala is a widespread lingua franca here) who have tended to be both centralist (thus, anti-Kasavubu) and cautious (thus, anti- Lumumba). The (Ba-)Mbala (old allies of Lumumba's own Tetela) and other peoples from the area of the Kwango and Kwilo rivers are also numerous in Leo city, their leaders in the Parti Solidaire Africain (PSA) being the leftist Antoine Gizenga (23) and the rightist Cleophas Kamitatu.