The Republic of Zambia was inhabited for thousands of years by Khoisan-speaking hunter-gatherers. In the twelfth century CE, migrations of Bantu-speaking tribes (including the Tonga and Nkoya) pushed into these traditional areas and absorbed most of the Khoisan. Further tribal settlements occurred in the 18th and 19th centuries, with the arrival of the Nsokolo, Ngoli and Sotho people. Europeans first arrived in the late 18th century, the most prominent of whom was David Livingstone who reached the Zambezi River in 1855 and naming the magnificent falls there after Queen Victoria.
The British South Africa Company under Cecil Rhodes obtained mineral rights from a local king in 1888, and a few years later his British South Africa Police (BSAP) put down a rebellion in the east, thereafter naming the region North-eastern Rhodesia. In 1911 it merged with the North-western section to form Northern Rhodesia, which became a British colonial holding in 1923. The land to the south (now Zimbabwe) was at this time known as Southern Rhodesia, but in 1953 the British government merged both territories (along with Nyasaland, now Malawi) into a single union called the Federation of Rhodesia and Nyasaland. The negative reaction to this union by the African population of Zambia led to a number of demonstrations and a state of crisis in the north. The United National Independence Party (UNIP) under Kenneth Kaunda would ultimately take up the cause of Zambian independence which lasted through 1962 and 1963. When Kaunda won a general election in 1964, he became the first Prime Minister of the new Republic of Zambia.
During subsequent years, Kaunda's government would support a number of African nationalist movements, including UNITA (Angola), the Zimbabwe African People's Union (ZAPU), the African National Congress (ANC), and the South West Africa People's Organization (SWAPO), and would establish close relations with both the Soviet Union and communist China. During the Rhodesian War, Zambia's border with its southern neighbor was closed, severely restricting the nation's intake of imports and supplies. Insurgent groups, in particular ZIPRA, were given refuge, training and military supplies by the Zambian government, and the military training camps would become frequent targets for external military operations by both Rhodesia and South Africa. Despite riots and protests against his regime in the 1990s, Kenneth Kaunda remained president until open elections were held in 1991.The Zambian Defence Force (ZDF) consists of the Army, Air Force and the Zambian National Service with approximately 15,000 active duty personnel. The latter is an internal defence type organization. In recent years, Zambian forces have taken part in peacekeeping operations to other African nations.