The Lisbon treaty was ratified on the 3rd of November 2009 with the Czech Republic as the last country to ratify it.
The treaty has undergone a long process and faced many challenges as the treaty had to be ratified by all member countries before it could come into force. It started with a proposed European Constitution that was thrown out by French and Dutch voters in 2005. The constitution was replaced by the Lisbon treaty which was later rejected by the Irish voters in 2008, but was finally accepted in a second referendum in Ireland in 2009. And the treaty is now ready to be implemented from December 2009.