Kigali Gisaka. By playing these neighbours against each other, the early kingdom flourished in the area, expanding westwards towards Lake Kivu and taking the Kigali area in the process. In the late 16th or early 17th centuries, the kingdom of Rwanda was invaded by the Banyoro and the kings forced to flee westward, leaving Kigali and eastern Rwanda in the hands of Bugesera and Gisaka. The formation in the 17th century of a new Rwandan dynasty by mwami Ruganzu Ndori, followed by eastward invasions and the conquest of Bugesera, marked the beginning of the Rwandan kingdom's dominance in the area. The
Kigali three administrative districts—Nyarugenge, which lies in the south west, Kicukiro in the south east, and Gasabo, which occupies the northern half of the city's territory. Kigali lies in a region of rolling hills, with a series of valleys and ridges joined by steep slopes. Kigali lies between the two mountains of Mount Kigali and Mount Jali, both of which have altitudes over , while the lowest areas of the city have an altitude of . Geologically, the city lies in a granitic and metasedimentary region, with lateritic soils on the hills and alluvial soils in the valleys. The Nyabarongo River,