Nevertheless, in 1959 France amended the constitution to allow other colonies this option. As Shillington describes farmers in British East Africa were upset by attempts to take their land and to impose agricultural methods against their wishes and experience. In Tanganyika, Julius Nyerere exerted influence not only among Africans, united by the common Swahili language, but also on some white leaders whose disproportionate voice under a racially weighted constitution was significant. He became the leader of an independent Tanganyika in 1961. In Kenya, whites had evicted African tenant farmers in the 1930s; since the '40s there has been conflict, which intensified in 1952. By 1955, Britain had suppressed the revolt, and by 1960 Britain accepted the principle of African majority rule. Kenya became independent three years later. Shillington vividly portrays Belgium's initial opposition to independence, the demands by some urban Africans, the 1957 & 1958 local elections meant to calm this dissatisfaction, the general unrest that swept the colony, the rapid granting of independence and the civil strife that ensued. The main period of decolonisation in Africa began after World War II. Growing independence movements, indigenous political parties and trade unions coupled with pressure from within the imperialist powers and from the United States and the Soviet Union ensured the decolonisation of the majority of the continent by 1980. While some areas, in particular, South Africa, & Namibia retain a large population of European descent, only the Spanish enclaves of Ceuta and Melilla and the islands of Réunion and Mayotte, the Canary Islands, and Madeira remain under European control, the latter two of which were never part of any African polity and have an overwhelmingly European population. The theory of colonialism addresses the problems and consequences of the colonisation of a country, and there has been much research conducted exploring these concepts. Mahmood Mamdani wrote his book "Citizen and Subject" in 1996. The main point of his argument is that the colonial state in Africa took the form of a bifurcated state, “two forms of power under a single hegemonic authority”. The colonial state in Africa was divided into two. One state for the colonial European population and one state for the indigenous population. The colonial power was mainly in urban towns and cities and were served by elected governments. The indigenous power was found in rural villages and were ruled by tribal authority, which seemed to be more in keeping with their history and tradition. Mamdani mentions that in urban areas, native institutions were not recognised. The natives, who were portrayed as uncivilised by the Europeans, were excluded from the rights of citizenship.