The Thebans had taken advantage of Alexander's absence from Greece to revolt against Macedonian domination. The city was destroyed and its inhabitants were enslaved to serve as an example.
Citation:
Bouchard, Elsa. "Destruction of Thebes".
The Literary Encyclopedia. First published 01 March 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=11281, accessed 20 May 2013.]