There’s a version of the story of Hanukkah, the Jewish holiday that begins on Sunday evening, that many modern-day celebrants probably know. It goes like this: During a celebration of taking back the Jewish temple, oil that was supposed to last just one night ended up lasting eight. Therefore, it was a miracle and to celebrate, we light a menorah for eight nights and eat foods cooked in oil, like latkes and doughnuts.

But David Kraemer, the Joseph J. and Dora Abbell Librarian and Professor of Talmud and Rabbinics at the Jewish Theological Seminary, says the full Hanukkah story is much longer and much more convoluted—and, as with so many of the stories behind religious holidays, it’s hard to corroborate the story with non-religious evidence.

“The problem is that we don’t have really good sources for what happened in the 170s BCE,” Kraemer says. “The sources we have are not only unclear but, depending on how you read them, they’re even contradictory with one another.”