Marathon Myth

I've known the myth behind the modern 26 mile marathon to be the 26 miles between the cities of Marathon and Athens in Greece. Phidippides ran the 26 miles to Athens to warn of an upcoming invasion and ask for help. He then ran back to Marathon, and died of exhaustion upon arrival. This story is apparently wrong. It is an even more impressive run than the 26 miles between Marathon and Athens.... 142 miles between Marathon and Sparta! Twice! And he didn't even have Clif Bars.