 The ethnic categorization of the two was an imposed and an arbitrary construct based more on physical characteristics than ethnic background.However, the social differences between the Hutu and the Tusi have traditionally allowed the Tutsi, with a strong pastoralist tradition, to gain social, economic, and political ascendancy over the Hutu, who were primarily agriculturalists.The distinction under colonial powers allowed Tutsis to establish ruling power until a Hutu revolution in 1959 abolished the Tutsi monarchy by 1961.