Nov 1, 1993. The Maastricht Treaty went into effect on this day, formally establishing the European Union. The treaty was drafted in 1991. By 1993, 12 nations had ratified it. In 1995 three more nations ratified the treaty. The European Union grew out of the European Economic Community (also known as the Common Market), which was established in 1958.
November 1, 2017 all-day