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.
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 30 August 2014.]