It began with Pheidippides 2,500 years ago. Now it's your turn. Run.
In a powerful ad by the Wieden + Kennedy agency, Nike urges you to keep running. Even if you're dead last in the race, you can finish the race. You can become a runner simply by persisting.
-via American Digest
There is some question about the story of Pheidippides being true. It is generally referred to as "a legend." The distance of a marathon has been changed a few times - it went from 25 miles to 26 miles because it fit desirable starting and end points.