S. Kent Brown writes (The Anchor Bible Dictionary, v. 6, p. 668):
The date and place of composition remain obscure. Although the work was composed in Greek before it was translated into Coptic, whether it was written in Egypt or elsewhere is uncertain. Allusions to documents known from the NT, such as Matthew (Tuckett 1984) and certain Pauline Epistles (Menard 1972), place the date well into the 2d century, a period that harmonizes with the rising influence of Valentinus. The richly subtle and sophisticated style and organization of the text, designed to invite readers in an inoffensive way to a certain view of Jesus' salvific role (Attridge 1988), may argue for a later date.
Here is what Harold W. Attridge and George W. MacRae have to say about the dating of the Gospel of Truth (The Nag Hammadi Library in English, p. 38):
A Valentinian work entitled the "Gospel of Truth" is attested in the Adversus Haereses (3.11.9) of Irenaeus. Unfortunately the heresiologist reveals little about the content of the work, except that it differed significantly from the canonical gospels. Given the general Valentinian affinities of the text of Codex I, it is quite possible that it is identical with the work known to Irenaeus. If so, a date of composition in the middle of the second century (between 140 and 180 C.E.) would be established. On the basis of literary and conceptual affinities between this text and the exiguous fragments of Valentinus, some scholars have suggested that the Gnostic teacher himself was the author. That remains a distinct possibility, although it cannot be definitively established.
Valentinus flourished from c. 140 CE to his death c. 160 CE.
Go to the Chronological List of all Early Christian Writings
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