Sacerdotal state
A sacerdotal state is a state whose head is also an ecclesiastical leader designated by a religious body. An example of this kind of state is the Vatican City: its heads of state, the popes of the Catholic Church, have governed papal lands distinct from secular authority since the establishment of the Papal States in the 8th century AD. Andorra operates under a semi-sacerdotal system, as one of its co-heads of state is the bishop of Urgell, while the other is the head of state of France. However unlike the Vatican, the co-princes of Andorra are ceremonial and not closely involved in the government.
In the past, bishops commonly assumed temporal as well as spiritual authority and ruled as prince-bishops. This occurred, for example, in the Holy Roman Empire, where three of the seven imperial electors were prince-archbishops (those of Trier, Mainz and Cologne). After the 1648 Peace of Westphalia certain prince-bishoprics became bi-confessional and alternated between governance by Catholic bishops and by Protestant administrators.