16 July 1966
Nigeria became the first Anglophone, independent African state to become an associate member of the European Economic Community, (EEC). The move to become an associate member of EEC came less than a decade after the country gained its independence from Britain in October 1960. The EEC came into being on 25 March, 1957, when West Germany, France, Italy, Luxembourg, the Netherlands and Belgium signed a treaty in Rome, Italy. Also known as Common Market, the EEC was a major step in Europe's movement toward economic and political union. In the same year Nigeria experienced a major crisis. A small group of army officers, mostly South Eastern Igbos, overthrew the government and assassinated the federal Prime Minister and the Premiers of the Northern and Western regions. The federal military government that assumed power was unable to address ethnic tensions or produce a constitution acceptable to all sections of the country. Its efforts to abolish the federal structure greatly raised tensions and led to another coup in July.
References

History.com, ‘Common Market Founded’, [online], available at www.history.com (Accessed: 05 June 2012)|Boddy-Evans A, ‘This Day In African History: 16 July’, from About African History.com, [online], available at www.africanhistory.about.com (Accessed: 05 June 2012)]|South African History Online, ‘Nigeria’, [online], available at www.sahistory.org.za (Accessed: 05 June 2012)