Copies of all of the now lost plays of Sophocles and Euripides existed in Constantinople until 1203. At that time the city's libraries were burned down during the Fourth Crusade.
The Plague began to spread through Europe in 1348, brought there from rats on ships coming from the Near East. The accepted thought was that the disease was caused by Jews poisoning wells. So tens of thousands of them were massacred in Spain France and Germany.