Landeskirche

In Germany and Switzerland, a Landeskirche (plural – Landeskirchen) is the church of a region. They originated as the national churches of the independent states, States of Germany (Länder) or Cantons of Switzerland (Kantone, Cantons), that later unified to form modern Germany (in 1871) or modern Switzerland (in 1848), respectively.

In the pre-Reformation era, the organization of the church within a land was understood as a landeskirche, certainly under a higher power (the pope or a patriarch), but also possessing an increased measure of independence, especially as concerning its internal structure and its relations to its king, prince or ruler. Unlike in Scandinavia and England, the bishops in the national churches did not survive the Reformation, making it impossible for a conventional diocesan system to continue within Lutheranism. Therefore, Martin Luther demanded that, as a stop-gap, each secular Landesherr (territorial lord, monarch or a body, like the governments of republican Imperial estates, such as Free Imperial Cities or Swiss cantons) should exercise episcopal functions in the respective territories. The principle of cuius regio, eius religio also arose out of the Reformation, and according to this a Landesherr chose what denomination his subjects had to belong to. This led to closed, insular landeskirchen. The principle was a byproduct of religious politics in the Holy Roman Empire and soon softened after the Thirty Years' War.

At the time of the abolition of the monarchies in Germany in 1918, the Landesherren were summus episcopus (Landesbischöfe, comparable to the Supreme Governor of the Church of England) in the states or their administrative areas, and the ties between churches and nations came to be particularly close, even with Landesherren outside the Lutheran church. So the (Roman Catholic) king of Bavaria was at the same time supreme governor (summus episcopus) of the Evangelical Lutheran Church in Bavaria right of the River Rhine. In practice, the Landesherren exercised episcopal functions (summepiscopacy) only indirectly through consistories (German: Konsistorium/Konsistorien [sg./pl.]).

...
Wikipedia