There are nine indigenous tribes residing in Guyana: the Wai Wai, Macushi, Patamona, Lokono, Kalina, Wapishana, Pemon, Akawaio and Warao. Historically the Lokono and Kalina tribes dominated Guyana. Although Christopher Columbus was the first European to sight Guyana during his third voyage (in 1498), and Sir Walter Raleigh wrote an account in 1596, the Dutch were the first Europeans to establish colonies: Essequibo (1616), Berbice (1627), and Demerara (1752). After the British assumed control in 1796, the Dutch formally ceded the area in 1814. In 1831 the three separate colonies became a single British colony known as British Guiana.
Since its Independence in 1824 Venezuela has claimed the area of land to the west of the Essequibo River. Simón Bolívar wrote to the British government warning against the Berbice and Demerara settlers settling on land which the Venezuelans, as assumed heirs of Spanish claims on the area dating to the sixteenth century, claimed was theirs. In 1899 an international tribunal ruled the land belonged to Great Britain. The British territorial claim stemmed from Dutch involvement and colonization of the area also dating to the sixteenth century, which was ceded to the British.
Guyana achieved independence from the United Kingdom on 26 May 1966 and became a republic on 23 February 1970, remaining a member of the Commonwealth. The US State Department and the US Central Intelligence Agency (CIA), along with the British government, played a strong role in influencing political control in Guyana during this time. The American government supported Forbes Burnham during the early years of independence because Cheddi Jagan was identified as a Marxist. They provided secret financial support and political campaign advice to Burnham's People's National Congress, to the detriment of the Jagan-led People's Progressive Party, which was mostly supported by Guyanese of East Indian background.
In 1978, Guyana received international notice when 918 members of the American cult, Peoples Temple, died in a mass murder/suicide drinking cyanide-laced Flavor Aid. However, most of the suicides were by Americans and not Guyanese. More than 300 children were killed; the people were members of a group led by Jim Jones in Jonestown, the settlement which they had created. Jim Jones's bodyguards had earlier attacked people taking off at a small remote airstrip close to Jonestown, killing five people, including Leo Ryan, a US congressman.
In May 2008, President Bharrat Jagdeo was a signatory to the UNASUR Constitutive Treaty of the Union of South American Nations. Guyana has ratified the treaty.