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.
Citation:
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 23 May 2013.]