The so-called 'Passover Letter' is a tattered papyrus written in Aramaic during the Persian period. It is thought by scholars to contain the first extrabiblical reference to the rituals of Pesach, thus proving that this festival was already well established more than 2,400 years ago.The underlying article is published in the open-access Shaked Festschrift, to which I linked here. Gad Barnea has also published the full volume, including this article, at his Academia.edu site.Not so, says a new study by an Israeli researcher, which calls into question a century of scholarship on the seminal document and claims the text has little or nothing to do with Passover as we know it. Instead, the letter was most likely discussing Zoroastrian-inspired rituals that were commonly observed by Jews in the Persian Empire, says Dr. Gad Barnea, a lecturer in Jewish history and biblical studies at Haifa University.
[...]
For PaleoJudaica posts on the Aramaic "Passover" Papyrus from Elephantine, which doesn't actually mention Passover in its surviving text, see here and here and follow the many links. For another argument that the papyrus did not mention Passover at all, see here.
Dr. Barnea's argument involves technical aspects of ancient Zoroastrian worship outside my expertise, so I take no position on it. But I have made a case here that Passover as we know it was known, and perhaps well-known, in Judea no later than the third century BCE and quite possibly as early as the late seventh century BCE.
Visit PaleoJudaica daily for the latest news on ancient Judaism and the biblical world.