Colonial Nigeria refers to the area of West Africa, which became the modern day Nigeria, during the time British rule in the 19th and 20th centuries. British influence began with prohibition of slave trade to British subjects in 1807. The resulting collapse of African slave trade led to the decline and eventual collapse of the Edo Empire. Britain annexed Lagos in 1861 and established the Oil River Protectorate in 1884. British influence in the Niger area increased gradually over the 19th century, but Britain did not effectively occupy the area until 1885. Other European powers acknowledged Britain's power over the area in the 1885 Berlin Conference.
From 1886–1899, much of the country was ruled by Royal Niger Company, authorized by charter, and governed by George Taubman Goldie. In 1900, the Southern Nigeria Protectorate and Northern Nigeria Protectorate passed from company hands to the Crown. At the urging of governor Frederick Lugard, the two territories were amalgamated as the Colony and Protectorate of Nigeria, while maintaining considerable regional autonomy among the three major regions. Progressive constitutions after World War II provided for increasing representation and electoral government by Nigerians. The colonial period proper in Nigeria lasted from 1900 to 1960, after which Nigeria gained its independence.
Modern-day Nigeria has been the site of numerous kingdoms and tribal states over the millennia. The modern state originated from British colonial rule beginning in the 19th century, and the merging of the Southern Nigeria Protectorate and Northern Nigeria Protectorate in 1914. The British set up administrative and legal structures whilst practising indirect rule through traditional chiefdoms. Nigeria became a formally independent federation in 1960, and plunged into a civil war from 1967 to 1970. It has since alternated between democratically-elected civilian governments and military dictatorships, until it achieved a stable democracy in 1999, with its 2011 presidential elections being viewed as the first to be conducted reasonably freely and fairly.