Prior to the Nag Hammandi codices there was the Pistis Sophia. These writings are very old..they date from around 100-300AD. Today we are fortunate to have these early esoteric church texts to read and study. Most of the early christian literature was labeled heretical and destroyed by the Alexandrian doctors of religious thought...there are things in there that didn't mix well with those Neoplatonists. The Pistis Sophia was purchased in 1795 and was the largest repository of Gnostic beliefs before the unearthing, in 1945, of the Nag Hammandi Library. Like time capsules, these writings have come to us, in purity, ready to be studied. They give us some very good source material for what these early churches believed.
The Pistis Sophia is about things that transpired between the resurrected Jesus, the First and Last Mystery, and his disciples. An interesting point is that those disciples included both men and women. The text is filled with involvement in the physical cosmos, purification from sin and salvation through the infinite compassion of the First Mystery. The path is layed out for the initiate to obtain an inheritance in the Light-Kingdom. To get to this level requires receiving the mysteries, and the way to get the mysteries is to be righteous and good.
Rounded with mysticism, obscurity and allegory, this codex is well worth adding to the Christian reference shelf.