The Economic Community of Central African States (ECCAS; , CEEAC; , CEEAC; , CEEAC) is an Economic Community of the African Union for promotion of regional economic co-operation in Central Africa. It "aims to achieve collective autonomy, raise the standard of living of its populations and maintain economic stability through harmonious cooperation". History Customs and Economic Union of Central Africa The Customs and Economic Union of Central Africa (or UDEAC from its name in French, ), (in Spanish: , UAEAC), (in Portuguese: , UAEAC), established by the Brazzaville Treaty in 1964, formed a customs union with free trade between members and a common external tariff for imports from other countries. The treaty became effective in 1966 after it was ratified by the then five member countries—Cameroon, the Central African Republic, Chad, the Republic of Congo, and Gabon. Equatorial Guinea joined the Union on 19 December 1983. UDEAC signed a treaty for the establishment of an Economic and Monetary Community of Central Africa (CEMAC) to promote the entire process of sub-regional integration through the forming of monetary union with the Central Africa CFA franc as a common currency; it was officially superseded by CEMAC in June 1999 (through agreement from 1994). CEMAC currently operates a customs union and monetary union. The common market is in place, but many exceptions to the tariff free regime still exist. Foundation At a summit meeting in December 1981, the leaders of the UDEAC agreed in principle to form a wider economic community of Central African states. ECCAS was established on 18 October 1983 by the UDEAC members, São Tomé and Príncipe and the members of the Economic Community of the Great Lakes States (CEPGL established in 1976 by the DR Congo, Burundi and Rwanda). Angola remained an observer until 1999, when it became a full member. ECCAS began functioning in 1985, but was inactive for several years because of financial difficulties (non-payment of membership fees by the member states) and the conflict in the Great Lakes area. The war in the DR Congo was particularly divisive, as Rwanda and Angola fought on opposing sides. ECCAS has been designated a pillar of the African Economic Community (AEC), but formal contact between the AEC and ECCAS was only established in October 1999 due to the inactivity of ECCAS since 1992 (ECCAS signed the Protocol on Relations between the AEC and the regional blocs (RECs) in October 1999).