36 AFRICAN POLITICAL SYSTEMS
dates from this period, since the composition of the invading group still determines the title to chieftainships, rank, succession to various offices, and the order of precedence of a number of the older clans.
The Bemba are to all intents and purposes a homogeneous group. They form a quite distinct political unit from the Bisa, Lala, Lunda, and other neighbouring tribes with similar traditions of origin and marked cultural and linguistic affinities. The Bemba declare that their forefathers found the country empty on their arrival, and, whether this is true or not, there seems to have been no strong opposition from whatever groups occupied the territory. The war-like habits of this tribe seem to have developed later, when they spread into the surrounding districts, pushing back their neighbours, such as the Lungu to the north-west, the Bisa and the Lala to the west and south respectively, and the Cewa to the east. The dominance of the Bemba chiefs was still more effectively enforced by the import of Arab guns in the nineteenth century. Where they did not dislodge the occupants of the surrounding country, their chiefs appointed members of the royal family or specially faithful subjects to hold the district for him (ukulasJnka) and to collect tribute of ivory tusks, grain, ironwork, salt, or other goods. The empire of the Bemba extended at one time right up into the Congo and to the shores of Lake Tanganyika, and they exerted influence over most of the present Bisa and Lala country to the south. With the coming of the white man at the end of the nineteenth century, their authority over the surrounding tribes collapsed, and though Bemba chiefs still rule over Bisa villages, e.g. in the Chinsali and Luwingu districts, it is rather a case of tribal admixture on the borders than a large-scale incorporation of foreign elements such as has occurred in the history of some of the Southern Bantu states. For the purposes of the present inquiry, we can reckon the Bemba as a homogeneous tribe with a history of settled occupation of their present territory lasting about 200 years.
The distinctive marks of tribal membership are the following: (a) The common name Bohemia, still uttered with a good deal of pride in such phrases as 'Fzoe Babembct ('We, the Bemba'), used to preface bragging references to the exploits of the tribe as compared to those of surrounding peoples, who are still sometimes referred to contemptuously as slaves (bashya). (b) The common