Use the great feasts as landmarks without treating the list as exhaustive. This page starts with that question because it is the most useful way into the subject. It names the visible structure, keeps the vocabulary plain and points to the source trail instead of asking the reader to accept an unexplained conclusion.
The useful distinction here is between a pattern in the calendar and a date announced for one particular place. Fixed commemorations and the movable Paschal sequence can be studied together without being collapsed into one timetable. The Feast & Form Index gives this explanation a place among related records: feast, season, office, object or visual cue. That arrangement lets a reader arrive through ordinary language and leave with a more precise term.
The editorial boundary is deliberate. We do not assign a current schedule, repeat private contact details, or turn a local custom into a universal rule. When the evidence is limited, the page says so and offers a nearby source, such as the source register or the method note.
