Complex sentence: The Vatican City even though not a member of the European Union it has joined the eurozone in 2002 since it has a special agreement with the EU that allows this microstate to mint a limited number of euro coins.
Split into simpler sentences: The Vatican City even though it is not a member of the European Union it joined the eurozone in 2002. It has a special agreement with the EU that allows this microstate to mint a limited number of euro coins.