According to Epiphanius, the first distinctive appellation of Christians was Ιεσσαῖοι, Jessaeans, but it is doubtful from whom the title was derived, or in what sense it was applied. Some suppose it was from Jesse, the father of David; others (and with far greater probability of accuracy) trace it to the name of the Lord Jesus. Philo is known to have written a work on the first Church of St. Mark at Alexandria, which he himself entitled περὶ Ι᾿εσσαίων, which is now extant under the title of περἱ βίου θεωρητικοῦ (of the contemplative life), and so is cited by Eusebius even: Jerome, however, knew the work intimately, and for this reason gave Philo a place in his list of ecclesiastical writers. Eusebius also mentions the name Jessaeans as a distinctive appellation of the early Christians. Comp. Bingham, Antiq. bk. 1, ch. 1, § 1; Riddle, Christian Antiquities, p. 181.