Two of these referendums were held on the issue of the United Kingdom's relationship with Europe with the first held on the issue of continued membership of what was known at the time as the European Communities (EC), which was the collective term for the European Coal and Steel Community (ECSC), the European Economic Community (EEC) and the European Atomic Energy Community (EAEC), and was also referred to by many at that time as the "Common Market". This was the 1975 European Communities membership referendum which was held two and a half years after the United Kingdom became a member state on 1 January 1973 and was the first national referendum ever to be held within the United Kingdom. The second took place forty-one years later by which time the various European organisations (with the exception of EAEC) had been integrated by subsequent treaty ratifications into the European Union (EU) when the electorate was asked to vote again on the issue of continued membership in the 2016 European Union membership referendum.