Answer
De rerum natura was rediscovered in Germany in 1417 by Poggio Bracciolini, an Italian humanist and librarian, who found a copy of the manuscript in the library of the Benedictine monastery of Hersfeld Abbey. The manuscript, which had been copied in the late 13th century, was one of the few surviving copies of the work. Bracciolini took the manuscript back to Italy, where it was copied and circulated among scholars.