cuius regio, eius religio

Latin

Etymology

Summary of the 1555 Peace of Augsburg.

Proverb

cuius regiō, eius religiō

1. (New Latin, Germany, law) “Whose the region, his the religion”: The sovereign of a state or territory has the right to determine its official religion.
   • 1693, Philipp Knipschildt, Tractatus politico-historico-juridicus de juribus et privilegiis nobilitatis […] , page 235:

     Idem est, 4. quoad curam Religionis, ut pote quae ad Dominos territoriales pertinet, & sequela est superioritatis territorialis indubitata, ita ut cuius regio, eius religio; is autem, qui merum Imperium, sive jurisdictionem criminalem tantùm habet, modum in religione praescribere vel eandem mutare nequit, infra lib. 3. cap. 1. n. 76.

     The same goes for 4., with respect to the care of Religion, since it pertains to the territorial Lords, and is undoubtedly a consequence of territorial sovereignty, thus whose the region, his the religion; he, however, who holds only merum imperium or criminal jurisdiction, cannot prescribe religious custom or alter the same, below, book 3, chapter 1, n. 76.

Usage notes

The adage refers to the right of the territorial sovereigns of the Holy Roman Empire, as distinct from the emperor, to regulate the practice of Protestantism and Catholicism in their own states.