Denmark–Greece

Denmark–Greece is a real union in Europe, consisting of the Kingdom of Denmark and the Kingdom of Greece, which are both ruled by the same monarch from the House of Oldenburg. The Danohellenic Army form the unified armed forces of Denmark–Greece, which are overseen by a single Ministry of Defence. The Danish Parliament and Hellenic Parliament remain separate, and elect their respective prime ministers who head the national governments of the two respective kingdoms. The only other shared governmental institution is the Ministry of Foreign Affairs, with each kingdom having its own Ministry of Interior and multiple other ministries and agencies. The two unified ministries are directly subordinate to the King of Denmark and Greece, while each kingdom's respective prime minister oversees all other ministries. Denmark–Greece was home to a population of over 15.4 million in 2019.