Diarchies

Andorra, officially the Principality of Andorra, is a landlocked country on the Iberian Peninsula, in the eastern Pyrenees in southwestern Europe, bordered by France to the north and Spain to the south. Believed to have been created by Charlemagne, Andorra was ruled by the count of Urgell until 988, when it was transferred to the Diocese of Urgell. Andorra was formed as a polity by a charter in 1278, being a lordship within the Principality of Catalonia until 1715. It is currently headed by two co-princes: the Bishop of Urgell in Catalonia, Spain, and the president of France. Its capital and l

San Marino, officially the Republic of San Marino (RSM), is a landlocked country in Southern Europe, completely surrounded by Italy. Located on the northeastern slopes of the Apennine Mountains, it is the larger of two microstates within Italy, the other being Vatican City. San Marino is the fifth-smallest country in the world, with a land area of just over 61 square kilometres (24 sq mi) and a population of 34,042 as of 2025. Its capital, the City of San Marino, sits atop Monte Titano, while its largest settlement is Dogana, in the municipality of Serravalle.

Sparta was a prominent city-state in Laconia in ancient Greece. In antiquity (pre-800 BCE), the state was known as Lacedaemon (), while "Sparta" referred to its capital, a group of villages in the valley of the Evrotas River in Laconia, in southeastern Peloponnese. Around 650 BC, it rose to become one of the major military powers in Greece, a status it retained until 371 BC.

historical multinational monarchist state in Eastern Europe (Crown of the Kingdom of Poland and the Grand Duchy of Lithuania)

former sultanate in Anatolia

kingdom in Central Europe

Turkic dynasty

thumb|Kings of the Visigoths () by Alonso Cano

Document outlinining Spartan society and eugenics

sibling group