The Treaties of the European Union are a set of international treaties between the European Union (EU) member states which sets out the EU's constitutional basis. They establish the various EU institutions together with their remit, procedures and objectives. The EU can only act within the competences granted to it through these treaties and amendment to the treaties requires the agreement and ratification (according to their national procedures) of every single signatory.
There are two core functional treaties that lay out how the EU operates and a number of satellite treaties which are interconnected with them. The treaties have been repeatedly amended by other treaties over the 60 years since they first began. The modern amended versions are known as the "consolidated treaties".
The two principal treaties on which the EU is based are the Treaty on European Union (TEU; Maastricht Treaty, effective since 1993) and the Treaty on the Functioning of the European Union (TFEU; Treaty of Rome, effective since 1958). These main treaties (plus their attached protocols and declarations) have been altered by amending treaties at least once a decade since they each came into force, the latest being the Treaty of Lisbon which came into force in 2009. Lisbon also made the Charter of Fundamental Rights legally binding, though that is not a treaty per se. The troubled ratification of Lisbon has meant there is little climate for further reform in the next few years beyond accession treaties, which merely allow a new state to join.
The first deals with common provisions. Article 1 establishes the European Union on the basis of the European Community and lays out the legal value of the treaties. The second article states that the EU is "founded on the values of respect for human dignity, freedom, democracy, equality, the rule of law and respect for human rights, including the rights of persons belonging to minorities." The member states share a "society in which pluralism, non-discrimination, tolerance, justice, solidarity and equality between women and men prevail".