Mid 17th century; earliest use found in John Burges (1563–1635), Church of England clergyman and religious controversialist. From Byzantine Greek μυσταγωγικός from Hellenistic Greek μυσταγωγός + -ικός. Compare classical Latin mystagōgica (neuter plural), title of a work by Cincius (1st century b.c.), mentioned in a 2nd-cent. epitome of a 1st-cent. grammarian.