Josephus discusses the Pharisees, Sadducees, Essenes and insurrectionists (the “school of Judah”) in Book 18 of Antiquities; Philo discusses the Essenes in That Every Virtuous Man is Free, and the Therapeutae, a mysterious sect of celibate men and women, in On the Contemplative Life. With less enthusiasm, Philo speaks of “some Jews” who understand the true, allegorical meanings of the Laws and thus cease to observe them literally: “We shall be ignoring the sanctity of the Temple and of a thousand other things if we pay heed to nothing except what is shown us by the inner meaning of things”—a reference to the importance of keeping the purity laws (On the Migration of Abraham 16:89–93). According to Josephus, John the Baptist immersed Jews “for the purification of the body once the soul had been previously cleansed by righteous conduct,” (Antiquities 18:5). Two later texts, one Jewish (Tosefta Yada’im 2:20), one Christian (Eusebius, drawing on a late second-century writer Hegesippus, in his Ecclesiastical History 4:22), name another late Second Temple purity-group “the immersers.” I thank Dr. Oded Irshai of Hebrew University for this reference, and for his guidance through the Talmudic material on purity.