Everything substantial comes from Papyrus Berolinensis 8502, the Berlin Codex, a Coptic manuscript of the fifth century bought in Cairo in 1896 by the German scholar and diplomat Carl Reinhardt and taken to Berlin. Three other works share the codex: the Apocryphon of John, the Sophia of Jesus Christ and an episode from the Acts of Peter. Carl Schmidt prepared an edition, but on the standard account the printed sheets were destroyed by a burst water pipe at the Leipzig printers in 1912; the First World War, Schmidt's death in 1938 and the Second World War delayed matters further, and the edition was finally completed by Walter Till and published in 1955, by which time the Nag Hammadi codices had appeared and absorbed the attention the Berlin Codex might otherwise have had.
Two Greek fragments confirm a Greek original and second-century circulation: Papyrus Rylands 463, of the early third century, published in 1938, and Papyrus Oxyrhynchus 3525, also third century, excavated with the rest of the Oxyrhynchus material but not published until 1983. Both overlap parts of the Coptic, and both differ from it in wording, so the text was not stable.
The extent of the loss should be stated plainly, because it governs everything else. The work occupied about nineteen manuscript pages. Pages one to six are gone, and pages eleven to fourteen are gone. That is roughly ten pages missing out of nineteen: the whole opening, and the central section of Mary's vision, of which only the beginning and the closing stages survive. What is lost is precisely the content of the revelation that the surviving quarrel is a quarrel about. Any confident account of what the vision taught is reconstruction, and should be labelled as such.