Nigeria has been home to several indigenous pre-colonial states and kingdoms since the second millennium BC, with the Nok civilization in the 15th century BC marking the first internal unification in the country. The modern state originated with British colonialization in the 19th century, taking its present territorial shape with the merging of the Southern Nigeria Protectorate and Northern Nigeria Protectorate in 1914 by Lord Lugard. The British set up administrative and legal structures while practising indirect rule through traditional chiefdoms in the Nigeria region. Nigeria became a formally independent federation on October 1, 1960. It experienced a civil war from 1967 to 1970, followed by a succession of democratically-elected civilian governments and military dictatorships, until achieving a stable democracy in the 1999 presidential election; the 2015 election was the first time an incumbent president had lost re-election.