Game concept · By God Alone
Christendom
From the game's encyclopedia
Christendom encompasses the Realms of all Independent Christian Rulers who are members of The Christian Church Situation.
The game's text for patch 1.20.1.2. Words in blue are entries of the encyclopedia: hover one to read it, as in the game.
Christendom is an entry of Crusader Kings III's in-game encyclopedia (By God Alone). The game explains it: "Christendom encompasses the Realms of all Independent Christian Rulers who are members of The Christian Church Situation." Patch 1.20.1.2, from game/common/game_concepts/pam_game_concepts.txt and game/localization/english/game_concepts_l_english.yml.
Source: game/common/game_concepts/pam_game_concepts.txt, game/localization/english/game_concepts_l_english.yml and the English localisation, Crusader Kings III 1.20.1.2.