The contents of the codices were written in Coptic language, though the works were probably all translations from Greek.
The best-known of these works is probably the Gospel of Thomas, of which the Nag Hammadi codices contain the only complete text.
Unearthed in 1945 by a group of Egyptians digging for fertilizer, the so-called Nag Hammadi codices were one of the most important manuscript discoveries of the twentieth century for the study of religion in the late ancient Mediterranean world, particularly formative Christianity and Judaism.
The forty-six different tractates that the codices contain have provided scholars with a wealth of new data for understanding the development of early Christian traditions about Jesus; Gnostic, Valentinian, and other streams of Christian thought later considered to be heretical; and Coptic grammar, orthography, and codicology.
Although reports that he found thirteen codices in the jar, the present "Codex XIII" consists actually of leaves that had been removed from a codex in antiquity and placed into the cover of Codex VI.
The codices then passed into the hands of different antiquities dealers.
Most famously, Codex I ended up at the Jung Institute in Zurich; also known as the Jung Codex, it was one of the first codices whose tractates were published.
formerly attested only by the anti-heretical treatises of orthodox Christianity.
The best-known of these works is probably the Gospel of Thomas, of which the Nag Hammadi codices contained the only complete text.
The writings in these codices comprised fifty-two mostly Gnostic treatises, but they also include three works belonging to the Corpus Hermeticum and a partial translation/alteration of Plato's Republic.