Most of these headings can be searched more specifically with the subheadings:
Also, the subheading: "--History of Doctrines--middle ages, 600-1500" can be used for most theological topics (e.g.: "Salvation--history of doctrines--middle ages, 600-1500"). In addition, many related fields will have a heading specific to the middle ages, such as "Architecture, medieval."
Depending on one's area of research, it is also often possible to access information through a geographical subject heading (name of region/country--church history), or through the name of an individual in whom one is interested, or the name of a denomination or sect. For the latter, "Catholic Church" is used in LCSH as a pattern heading; that is, all subheadings that are widely used for religions and religious organizations are to be found under the Catholic Church heading. Additional subheadings that are specific to a religious group may be found under that group's own heading.