Several fragments of the Ascension of Moses have survived to the present, however, most of the work is likely lost forever. The Ascension of Moses is almost certainly the precursor to the Revelation of Metatron, in which Rabbi Ishmael was taken up to the sky by Metatron, the supreme archangel. In the Ascension of Moses, it was Moses who was taken up to the sky, and Metatron played a smaller role, although, clearly the same role in the Long Aramaic Revelation of Moses, which is the closest to Revelation of Metatron. In both the Long Aramaic Revelation of Moses and the Revelation of Metatron, Metatron identifies himself as Enoch, Moses' ancestor, which connects this clearly heretical Jewish work with the older Enochian literature. In the other surviving fragments, the connection is less clear, as is the cosmography of the seven skies, and it is, therefore, possible that there were several stages of textual development before the version that was redacted into the Revelation of Metatron. In the Revelation of Metatron, the role of Moses has been replaced by Rabbi Ishmael, a rabbi who lived in Palestine in the late-1st-century and early-2nd-century AD, however, his name was attached to most of the Merkabah literature in that circulated in Babylonia during between 400 and 1000 AD, and is universally considered to have been used to replace an earlier name. Chapter 15B of the Revelation of Metatron is itself an excerpt from the Ascension of Moses, which, if nothing else, proves that the Ascension has been viewed as an earlier copy of the Revelation since at least the 1000 AD, the latest the Revelation was likely to have been edited significantly.
It is not clear when Metatron first appeared within Judaism, however, he was present before he became associated with Enoch, as the story of Samyaza and Azazel demonstrate, which is set in the era of Enoch's ancestor Enosh. In the story of Samyaza and Azazel, Metatron already existed as the messenger of the Lord, meaning, he existed as an angel within some form of archaic Judaism before he became Enoch incarnate in the Ascension of Moses. The claim that Enoch, a man, could become an angel, or archangel, or Prince of all the Princes, is itself heretical within Rabbinical Judaism, where angels are viewed as a separate form of life, based on fire, or ice, or electricity, or some combination of 'elements' but not flesh made of 'dust.' Therefore this was likely part of the heresy of Rabbi Elisha and does appear to be missing from the oldest fragment, the Short Aramaic Revelation of Moses.
The story of Samyaza and Azazel, which like the Yiddish Ascension of Moses is a Yiddish story found among the Chronicles of Jarahmeel, also appears to be a very ancient story bordering about as close as a Jew could get to polytheism without actually crossing that imaginary line. It is included as an appendix as is seems relevant to the question of Metatron's origin within Judaism, however, it is its treatment of Astarah that reveals its true age. The name is a variation of Asherah, who is mentioned many times in the Hebrew Bible, generally in association with Ba'al. Her worship was banned by King Josiah in the Hebrew Book of Kings when he banned the worship of Ba'al and the armies of the sky (hosts of heaven). Archaeological evidence has proven that Jews (or possibly Essenes) continued to worship Asherah until the 6th century BC, during the early Persians era, which is missing from the Talmud's records.