Etymology

From Ecclesiastical Latin mysteriarches ‎(“one who presides over Christian sacraments”), from Ancient Greek μυστηριάρχης ‎(mustēriárkhēs, “one who rules over religious mysteries”), from μυστήριον ‎(mustḗrion) +‎ -άρχης ‎(-árkhēs), corresponding to mystery +‎ -arch.