The Four Desert Ascetics
The Orthodox calendar for August 18 commemorates four ascetics who lived in the desert. The Synaxarion states plainly that their names are unknown, and no further biographical detail, location, or date has been preserved.
Later liturgical listings, such as the OrthodoxWiki calendar for August 18, likewise note simply "four holy ascetics" without elaboration. They are remembered for the witness of the desert ascetic life, even though their identities have not survived in the record.