Between 1600 and 1900 Buganda expanded territorially and politically. Because it was this two pronged growth which ensured Buganda’s dominance of the interlacustrine region during the 19th Century, this paper will examine in detail the process which led to political centralization and territorial expansion. In the first instance we shall consider governmental and constitutional changes. Then we shall deal with the territorial changes which began in the 17th Century. A close study of the political and constitutional developments suggests that there have been four major developments in the government of precolonial Buganda.1 All these changes were closely connected with the country’s territorial expansion. The first development really belongs to what we may describe as “pre-historic times” because it covers the Kintu-Kimera period, on which we have insufficient information.11 It is, therefore, not until the coming to Buganda of more clans that historical accounts become detailed enough to enable us to reconstruct the history of Buganda of about 21 generations back.2 But even after correlating evidence from the clan histories, it still remains difficult to determine with confidence the exact territorial extent of Buganda before the reign of Nakibinge in the early decades of the 16th Century.