Andorra and the euro facto" used the EU's euro (the currency of the Eurozone states) as it had historically used the French franc and Spanish peseta. When those two currencies were replaced by the euro in 2002, the euro replaced the franc and peseta as the sole circulating currency in Andorra. Unlike the three other European microstates outside of the EU, Monaco, San Marino and the Vatican City, which adopted the euro when it was introduced, Andorra did not conclude a monetary agreement with the EU but rather used it unilaterally. These agreements gave the three microstates the right to issue their own euro
Euro only recognised as legal tender within the Order. In economics, an optimum currency area, or region (OCA or OCR), is a geographical region in which it would maximise economic efficiency to have the entire region share a single currency. There are two models, both proposed by Robert Mundell: the stationary expectations model and the international risk sharing model. Mundell himself advocates the international risk sharing model and thus concludes in favour of the euro. However, even before the creation of the single currency, there were concerns over diverging economies. Before the late-2000s recession it was considered unlikely that a state