Sulla's invasion of Athens came as a punishment for the city's support to Rome's most dangerous enemy, Mithradates VI.
Citation:
Bouchard, Elsa. "Sack of Athens by Sulla".
The Literary Encyclopedia. First published 01 March 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=11390, accessed 21 May 2013.]