The renewal and reinterpretation of documentary sources, drawn primarily from oral traditions, have provided new approaches to the history of the Kingdom of Burundi. The kingdom grew out of the Ganwa dynasty, which unified small central kingdoms under a patrilineal monarchic regime; initially of limited territorial scope, its successors expanded it while at the same time buttressing its power. The distribution of the kingdom's lands among princes of the blood stressed the fragmentation of the space, however, and led to regional rivalries that continued during occupation by first the Germans, then the Belgians. The establishment during the colonial period of a secular constitutional sovereign undermined the prestige of the monarchy, while territorial reorganization encouraged the development of new elites supported by successive foreign administrations.