The legal basis of the EU is split into primary law and secondary law.
Primary law is set out in the treaties establishing the European Economic Community, the European Coal and Steel Community, the European Atomic Energy Community, and the treaties amending them (for example, the Single European Act and the Maastricht, Amsterdam and Nice treaties).
Secondary laws are those adopted on the basis of primary law. They take the form of directives, regulations or decisions. Recommendations and opinions are also used. Verdicts of the Court can also be considered on a treaty level.
See also Primary law and Hierarchy of acts