What European country is reigned by not one, but 2 co-princes?

Explanation

The Principality of Andorra is a small landlocked country in southwestern Europe, formed in 1278. The role of monarch is exercised jointly by the two co-princes, the President of the French Republic and the Bishop of Urgell, Catalonia, Spain. This peculiarity makes the President of France, in his capacity as Prince of Andorra, the only reigning monarch actually elected in regular intervals by popular vote, though not by the people of Andorra.