The subsequent period shows signs of massive migratory movements in all parts of the Mediterranean Basin. As a result of this social dislocation, the Greeks apparently lost their knowledge of writing.
Citation:
Bouchard, Elsa. "Decline of the Mycenaean civilization and of the Hittite empire".
The Literary Encyclopedia. First published 01 March 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=11124, accessed 25 May 2013.]