On the subject of the subintroductæ or συνείσακτοι, one of the greatest difficulties and scandals of the early church, vide the article of Can. Venables in D.C.A. ii. 1937.  The earliest prohibitive canon against the custom is that of the Council of Elvira, a.d. 305.  (Labbe i. 973.)  The Canon of Nicæa, to which Basil refers, only allowed the introduction of a mother, sister, or aunt.  The still more extraordinary and perilous custom of ladies of professed celibacy entertaining male συνεισακτοι, referred to by Gregory of Nazianzus in his advice to virgins, ἄρσενα πάντ᾽ ἀλέεινε συνείσακτον δὲ μάλιστα, may be traced even so far back as “the Shepherd of Hermas” (iii. Simil. ix. 11).  On the charges against Paul of Samosata under this head, vide Eusebius, vii. 30.