The Constitution was amended in 1972 to enable Ireland to accede to the European Communities. Upon accession, the treaties establishing the European Communities, as they stood in 1972, were made part of Irish law by the European Communities Act 1972. Subsequent amendments to these treaties were enabled, as necessary, by further amendments to the Constitution and the 1972 Act was also amended accordingly.
The last such amendment of the Constitution was effected to enable Ireland’s ratification of the Treaty of Lisbon.
A full list of the treaties establishing the European Communities and the European Union as incorporated into Irish law is set out in a consolidated version of the European Communities Acts 1972 to 2012, which is available on the website of the Law Reform Commission (http://www.lawreform.ie/revised-acts.84.html).