it was created in 1999, but until 1 january 2002 it was used only for electronic payments. in 2002, 12 countries of the european union (eu) took their state currencies out of circulation and adopted euro notes and coins as their only money. there was a change-over period, called the "transition period", when both the old national money and the euro were accepted, but by 28 february 2002, all 12 countries were using just euros.