Four commemorative coins have been issued jointly:
in March 2007, to commemorate the 50th anniversary of the Treaty of Rome
in January 2009, to celebrate the 10th anniversary of Economic and Monetary Union
in January 2012, to commemorate ten years of euro banknotes and coins
in August 2015, to celebrate the 30th anniversary of the EU flag
As a rule, euro countries may each issue only two €2 commemorative coins per year. Exceptionally, they are allowed to issue a third, provided that it is one issued jointly and that it commemorates events of Europe-wide importance.
These coins use a common design on the national side, showing the name of the issuing country as well as the event commemorated in the respective languages.