threat was posed by the refugees until the 1990s, when a civil war initiated by the Tutsi-refugee Rwandan Patriotic Front (RPF) forced the Hutu government into negotiations. This led to a rise in Hutu extremism and the 1994 genocide, in which over 500,000 Tutsi were killed before the RPF took control. Background Precolonial Rwanda The earliest inhabitants of what is now Rwanda were the Twa, a group of aboriginal pygmy hunter-gatherers who settled the area between 8000 and 3000 BC and remain in the country today. Between 700 BC and 1500 AD, a number of Bantu groups migrated into Rwanda and began clearing forests for agriculture. After losing much of their habitat, the forest-dwelling Twa moved to the mountains. Historians have several theories about the Bantu Migrations. According to one, the first settlers were Hutu; the Tutsi migrated later and formed a distinct racial group, possibly of Cushitic origin. An alternative theory is that the migration was slow and steady, with incoming groups integrating into (rather than conquering) the existing society. In this theory the Hutu-Tutsi distinction arose later as a class distinction, rather than a racial one. The population coalesced, first into clans (ubwoko) and into about eight kingdoms by 1700. The country was fertile and densely populated, with its kingdoms strictly controlled socially. The Kingdom of Rwanda, ruled by the Tutsi Nyiginya clan, became increasingly dominant beginning in the mid-18th century. From its origins as a small toparchy near Lake Muhazi the kingdom expanded through conquest and assimilation, reaching its zenith under King (Mwami) Kigeli Rwabugiri between 1853 and 1895. Rwabugiri expanded the kingdom west and north, implementing administrative reforms which included ubuhake (where Tutsi patrons ceded cattle—and privileged status—to Hutu or Tutsi clients in exchange for economic and personal service) and uburetwa (a corvée system in which Hutu were forced to work for Tutsi chiefs). Rwabugiri's reforms developed a rift between the Hutu and Tutsi populations. Colonisation The Berlin Conference of 1884 assigned the territory to Germany, with imprecise boundaries. When Gustav Adolf von Götzen explored the country ten years later, he discovered that the Kingdom of Rwanda included a fertile region east of Lake Kivu. Germany wanted this region, which was also claimed by Leopold II as part of his own Congo Free State (annexed by Belgium to form the Belgian Congo in 1908). To justify its claim, Germany began a policy of ruling through the