By the mid-16th century, the Burundi Kingdom had been established. The pastoralist Tutsi imposed their rule over the local Hutu farmers.
By the mid-17th century, the Burundi Kingdom began to expand outward, and by the first half of the 19th century, King Otar Rugamba had unified most of Burundi and captured parts of present-day southern Rwanda and western Tanzania. However, this kingdom failed to establish a centralized ruling system and remained in a state of decentralized fragmentation for a long time.
The central and western regions of Burundi consist mainly of plateau terrain, while the terrain between them and the East African colonies is basically an unbroken plain.
The main force responsible for defending the Burundi Kingdom was the army and militia stationed at Soron Lake in East Africa, which formed the western section of the Great Lakes to Soron Lake defense line.
