A fragment of Homer's "Odyssey" Book 12 sat unnoticed for decades in Utrecht University's archives until a Radboud University professor recognized it.
https://www.foxnews.com/travel/damaged-fragment-deemed-unremarkable-turns-out-rare-piece-homers-odyssey
https://www.foxnews.com/travel/damaged-fragment-deemed-unremarkable-turns-out-rare-piece-homers-odyssey