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 part of the upper headwaters of the Nile, forms the western and southern borders of the administrative city of Kigali, although this river lies somewhat outside the built-up urban area. The largest river running through the city is the Nyabugogo River, which flows south from Lake Muhazi before flowing west between Mount Kigali and Mount Jali, and draining into the Nyabarongo. The Nyabugogo is fed by various smaller streams throughout the city, and its drainage basin contains most of Kigali's territory, other than areas in the south which outflow directly to the Nyabarongo. The rivers are flanked by wetlands, which