The story begins in the 19th century, when scholars across Europe were rummaging through medieval manuscripts in old libraries and religious houses. Russian scholars were researching a medieval judicial codex called the Just Balance (Merilo Pravednoe), a collection of historical laws and commentaries. It was not surprising that a legal work compiled in the 14th century should include abundant religious and biblical-sounding material, but much of it sounded bizarre. The manuscript proved to contain an otherwise unknown pseudo-biblical book, 2 (Slavonic) Enoch, or the Book of the Secrets of Enoch. The second book of Enoch tells how the ancient patriarch traveled through the heavens, guided by angels, and witnessed the fate of spiritual beings, good and evil. It clearly stems from a world in which Enoch was seen as the source of vast bodies of esoteric wisdom. 2 Enoch foreshadows dozens of other apocalyptic works and tales of heavenly journeys, up to and including the works of Dante himself.Slavonic literature is not my specialty, but I know enough to want to nuance the claim in the last quoted sentence. Some material in the shorter version of 2 Enoch may well go back to as early as first-century C.E. Judaism, but the Greek text went through a long period of transmission in the Byzantine period, then it was translated into Old Church Slavonic and again underwent a long period of transmission before the surviving late medieval manuscripts were produced. There is reason to doubt that what we have now, even in the linguistically older short version, is a pristine exemplar of any putative first-century text. It should also be noted that fragments of the short version in Coptic have also been discovered (see here).
2 Enoch was probably written in Greek and was then translated into other languages, but the vast majority of what we know comes from these Slavonic texts. It survives in both longer and shorter versions, and the longer has clearly been adapted for Christian purposes. The shorter, older version takes us back to a work written by an Alexandrian Jew somewhere around the 1st century AD—roughly the time of the Dead Sea Scrolls.
The similarity between the ancient apocrypha and much later Dualist ideas could be a coincidence, but it is far more likely that those Slavonic writings themselves helped Eastern European thinkers move in Dualist directions during the tenth century. If that idea is correct, we would be looking at a direct influence from the long-extinct fringes of Second Temple Judaism through the heresies of medieval Europe.Maybe. That's an interesting possibility.
A new edition of the Slavonic text of 2 Enoch was published by Grant Macaskill in 2013. And follow the links there for additions background on 2 Enoch, plus see here. Professor Macaskill also wrote a few relevant online essays for our class on the Old Testament Pseudepigrapha some years ago: The Slavonic Pseudepigraph: An Introduction, An Introduction to 2 Enoch, and Enoch and Salvation. And more on Old Church Slavonic and other Slavonic pseudepigrapha is here with many links.
Cross-file under Old Testament Pseudepigrapha Watch.