Hunter-gatherers settled the territory in the Stone and Iron Ages, followed later by Bantu peoples. The population coalesced first into clans and then into kingdoms. The Kingdom of Rwanda dominated from the mid-eighteenth century, with the Tutsi kings conquering others militarily, centralising power and later enacting anti-Hutu policies. Germany colonised Rwanda in 1884 as part of German East Africa, followed by Belgium, which invaded in 1916 during World War I. Both European nations ruled through the kings and perpetuated a pro-Tutsi policy. The Hutu population revolted in 1959. They massacred numerous Tutsi and ultimately established an independent, Hutu-dominated republic in 1962 led by President Grégoire Kayibanda. A 1973 military coup overthrew Kayibanda and brought Juvénal Habyarimana to power, who retained the pro-Hutu policy. The Tutsi-led Rwandan Patriotic Front launched a civil war in 1990. Habyarimana was assassinated in April 1994. Social tensions erupted in the Rwandan genocide that followed, in which Hutu extremists killed an estimated 500,000–1,000,000 Tutsi and Hutu in the span of one hundred days. The RPF ended the genocide with a military victory in July 1994.