The Testament of Isaac has survived in Coptic, Arabic, and Ethiopic. Of the Coptic there are two versions, one in Sahidic and one in Bohairic, each extant in only a single MS. The Sahidic version is found as the second of four items in a MS in the Pierpont Morgan collection in New York (M 577, dated AD 894/5), and the Bohairic in Cod. Vat. Copt. 61 (dated AD 961/2) where it is grouped together with the Testaments of Abraham and Jacob as the fifth item in a series of ten. Both the Arabic and Ethiopic versions agree with the Bohairic in offering texts of all three Testaments and also in grouping them together.
Guidi, in the Introduction to his edition of the Bohairic text of the Testaments of Isaac and Jacob,1 argued that both are imitations of the Testament of Abraham and that both were composed in Coptic. In this case the Arabic and Ethiopic versions will have been derived from the Coptic. And this hypothesis may be supported by the observation that the later versions follow the Bohairic, not only in grouping the Testaments of Abraham, Isaac, and Jacob, together as a unit, but also in attributing them in their present form to St. Athanasius.2
On the other hand, even if it be conceded that the two later Testaments are imitative, that is no reason why they should not have been composed in Greek, although the Greek originals have not as yet come to light. If the reference to the book, or books, 'of the three Patriarchs' in The Apostolic Constitutions (VI.xvi.3) is to our Testaments of Abraham, Isaac, and Jacob, then there must have been a Greek Isaac and a Greek Jacob as well as a Greek Abraham. Similarly, it might be argued that the enigmatic passage in Priscillian ( tract. iii) shows that Priscillian knew a Latin version of all three Testaments,3 and that this is further evidence in favour____________________