It later dawned on me that "Cathari" was a term for heretics in Middle Ages.
"From the Greek katharos, pure; literally "puritans", a name specifically applied to, or used by, several sects at various
periods. The Novatians of the third century were frequently known as Cathari, and the term was also used by the
Manichæans. In its more usual sense, Cathari was a general designation for the dualistic sects of the later Midde
Ages. Numerous other names were in vogue to denominate these heretics."