Which European Union?: Europe after the Euro crisis
"In the EU experience, the very concept of union was formally used for the first time in the preamble of the 1957 Rome Treaty establishing the European Economic Community (EEC), when the signatory states expressed their determination "to lay the foundations of an ever-closer union among the peoples of Europe". This concept was then strengthened in the 1992 Maastricht Treaty or Treaty establishing the European Union (TEU), when the signatory states reaffirmed in the Treaty's preamble their resolution "to continue the process of creating an ever closer union among the peoples of Europe""--