For the reformed treaty to come into being, the EU has had to work through a number of predecessors and all the problems which come with getting a large collection of independent states to think and agree as one.
The European Reform Treaty has taken a circuitous route to Lisbon and agreement
DW-WORLD.DE looks at the long road which led to Lisbon.
December 10, 2000
EU heads of state and government agree on a new EU treaty after long-drawn-out talks in Nice. The EU currently runs according to the rules established in those talks.
December 15, 2001
Recognizing the difficulty of the issues raised in Nice, EU leaders meeting in Laeken (Belgium) agree to set up a Convention on the Future of the EU chaired by French ex-president Valery Giscard d'Estaing.
February 28, 2002
The convention holds its first meeting.
February 1, 2003
The Nice Treaty comes into force.
April 16, 2003
In Athens, 10 states, eight of them from central and eastern Europe, sign treaties of accession to the EU, paving the way for the Union's expansion to 25 members on May 1, 2004. The enlargement makes an overhaul of the EU's rules even more pressing.
July 20, 2003
The convention presents its proposal for an EU Constitutional Treaty.
May 1, 2004
The EU enlarges to 25 members.
June 17, 2004
EU heads meeting in Brussels agree on a text for the Constitutional Treaty, which they sign on October 29, 2004.
May 29, 2005
French voters reject the Constitutional Treaty in a referendum.
June 1, 2005
Dutch voters reject the treaty in a referendum.
June 17, 2005
EU heads agree on a one-year "period of reflection." A year later, they agree to reopen the debate on the EU's operating rules.
March 25, 2007
EU leaders issue the "Berlin Declaration" on the 50th anniversary of the EU's creation, confirming their determination to create a new legal basis for the EU.
June 23, 2007
After all-night talks in Brussels, EU leaders agree to a detailed mandate for the drafting of a new set of rules, which is to be called the reform treaty.
July 23, 2007
An EU Intergovernmental Conference (IGC) begins work to draft the treaty.
October 5, 2007
The IGC publishes its draft text just two weeks before EU leaders are due to meet in Lisbon to discuss it on October 18-19.