The Four Hundred were an oligarchic council that overthrew the democracy and briefly seized power in Athens. The military failures of the oligarchs during the war quickly brought about their downfall.
Bouchard, Elsa. "Revolution of the Four Hundred at Athens". The Literary Encyclopedia. First published 01 March 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=11236, accessed 20 September 2014.]