Rufinus of Aquileia (d. 410) was indeed a detractor of Jerome (on Rufinus in general, see Patrology, ed. Di Berardino IV, 247–54 and EEC II, 746). Although at an earlier stage of their lives Jerome and Rufinus had been close friends, differences of opinion concerning the theology of Origen (whose Greek writings both had translated into Latin) erupted in 399 into a virulent controversy. Rufinus composed an Apologia contra Hieronymum in two books (CCSL 20, 37–123); Jerome replied in 401 with a two-book Apologia aduersus libros Rufini (PL 23, 397–456). When Rufinus received a copy of Jerome's work, he wrote, apparently by return of post, a savage personal letter which unfortunately has not survived, but whose outline is known from Jerome's equally savage reply (written in 402) which is usually printed as the third book of his Apologia aduersus libros Rufini (PL 23, 457–92). On the controversy, see Cavallera, Saint Jérôme I, 193–286 and Kelly, Jerome, pp. 227–58. The Commentator may have been referring to these works, or to others now lost (see below).

Cassianusque. This is presumably John Cassian (c. 360 – c. 450), the so-called founder of western monasticism: see P. Munz, ‘John Cassian’, JEH 11 (I960), 1–22, O. Chadwick, John Cassian, 2nd ed. (Cambridge, 1968), Patrology, ed. Di Berardino IV, 512–23 and EEC I, 149.