Most of what is known about the Gnostic use of the word comes from a cache of Coptic manuscripts found by chance in 1945 near Nag Hammadi in Upper Egypt, buried in a sealed jar, which preserved gospels, revelations and treatises that the developing Christian church had largely suppressed or let disappear. The Gospel of Thomas, a list of sayings attributed to Jesus with no narrative around them, and the Gospel of Truth, closer to a homily on the nature of ignorance and knowledge, are the best known. Before that find, almost everything known of Gnostic teaching came through the writings of its opponents, chiefly Irenaeus of Lyon, who catalogued and refuted it at length in the second century, so the discovery let Gnostic Christians speak in their own words for the first time in centuries.
The core dispute with the emerging orthodox church was not academic. Gnostic teachers commonly held that the material world was the flawed product of a lesser being, the demiurge, rather than the direct work of the highest God, and that salvation meant recovering a divine spark trapped in matter through knowledge rather than through faith, sacrament or the death of Christ understood as a saving event in history. Orthodox writers treated this as a denial that creation and the body were good, and as a claim that grace could be bypassed by an elite capable of the higher knowledge. Hermetic gnosis, transmitted through a different and largely non-Christian body of Greco-Egyptian texts, shares the vocabulary and the inward method without the same quarrel over creation, which is why the term gnosis outlived the Christian controversy that made it famous.