A few years ago a Paris apartment was rediscovered where the owner had fled the Germans in 1940 and had locked it and the room remained sealed for decades.
I wonder if something like a medieval study or ancient library (something other than a tomb) had been sealed off and then later rediscovered.
in a way Pompeii and Herculaneum are exactly that. They were "sealed" after the eruption of Vesuvius and have been very well preserved. the think they may have even found a way to read the burned scrolls in the libraries of those two cities!