EUR-Lex is your online gateway to EU law. It provides the official and most comprehensive access to EU legal documents dating back to the beginning of the European Union.

See for example

Official Journal (from the first edition in 1952 until today)

Chronological overview of the Treaties

The Court of Justice of the EU's InfoCuria database contains all the publicly available information concerning the cases brought before the Court of Justice, the General Court and the Civil Service Tribunal.

DORIE (which stands for DOcumentation et Recherche sur les questions Institutionnelles Européennes) is a database providing access to the collection of documents put together over the years by the unit in the Secretariat-General responsible for institutional issues. The time period covered in DORIE goes from 1946 (oldest document available in the application) until nowadays.