The Olympic Games were a religious event celebrated once every four years at Olympia, a sanctuary of Zeus in Western Peloponnese, up until 393 AD. It attracted contestants from all over the Greek world.
Bouchard, Elsa. "First recorded Olympic Games". The Literary Encyclopedia. First published 01 March 2010
[http://www.litencyc.com/php/stopics.php?rec=true&UID=11134, accessed 30 September 2014.]