Game concept · By God Alone
The Christian Church Chapter
The game also links it as The Christian Church Chapters, Chapter, Chapters.
From the game's encyclopedia
Chapters are the Situation Phases of The Christian Church. There are seven total chapters, organised in four Chapter Types.
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.
The Christian Church Chapter is an entry of Crusader Kings III's in-game encyclopedia (By God Alone). The game explains it: "Chapters are the Situation Phases of The Christian Church." It is part of The Christian Church. The game also links it as The Christian Church Chapters, Chapter and Chapters. 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.