The traditional explanation of the difference between these two groups is that the Hutu, the Bantu-speaking farmers, lived there first but were conquered by the Tutsi, Hamatic cattle-keepers who came from the north about 400 years ago. The Tutsi then formed a permanent and separate aristocracy and kept the Hutu as serfs and underlings. Some anthropologists these days argue that the process was not achieved by foreign conquest but emerged from within the society. Today the two groups, easily distinguishable in their stereotypes, have become inextricably bound up in a hierarchical social system.
When the two kingdoms were taken over by Germany at the end of the last century and then turned over to Belgium as protectorates after the First World War, the imperial rulers reinforced the existing social system. Tutsi chiefdoms were maintained and Tutsis given preference in education and advancement. At independence the Tutsi aristocracy turned into an elite. In both Rwanda and Burundi the Hutu outnumber the Tutsi by about six to one.
They are among Africa's smallest countries and two of the poorest but they are also the most densely populated, the steep rolling hills cultivated from top to bottom in small subsistence plots of maize and bananas. The two ethnic groups live on the same hillsides and are no longer distinguishable by wealth or status. They speak the same language, Kirundu, and share the same culture. There have been increasing instances of inter-marriage though the children always belong to the ethnic group of the father. Many people had come to believe that the pathological rivalry between the two ethnic groups was a thing of the past.
In Burundi, the Tutsis maintained their power and status until last year, but in Rwanda the Hutus took power soon after independence. Hundreds of thousands of Tutsis were driven out following massacres and those that remained were subjected to discrimination. Rwandese must carry identity cards which bear their ethnic group and there have been numerous instances of Tutsi children being shunned or humiliated in schools and many cases of adults being refused jobs or houses.
In 1990, the Tutsi exiles in Uganda formed the Rwanda Patriotic Front and launched an invasion. Out of this came the coalition government of President Juvenal Habyarimana, a dictator for 20 years past: his death last week triggered the current killings.