It was the battle that inspired Byron to dream that "Greece might still be free".
Now, 2500 years on, Greeks hope the defeat of the Persians at Marathon will serve another, more modern purpose - saving their country from insolvency.
As a record number of athletes today mark the landmark anniversary, gathering in the Greek capital to run the 38.62km course which legend records was covered by the Athenian foot soldier Phidippides, the socialist Government is pulling out all the stops.
"Our hope is that this will herald the start of an international movement," said Nicolas Kanellopoulos, head of the Greek Tourism Organisation.
Rarely has an event been celebrated with such enthusiasm. In a bid to address the modern affliction of debt and budget deficit, the cash-strapped Greeks have cashed in on the prowess of their ancient forebears as never before.
Coins have been minted, statues unveiled, live concerts mounted and exhibitions held as officials showcase the run and its history.
Never mind that the prize money is minimal - at €1.5 million ($2.73 million), the winner's takings fall far short of the prizes in Boston and Berlin.
Or that, in contrast to modern marathons (the 26 mile 385 yard - or 42.195km - length of which was introduced in 1908), the long-distance run will be an uphill struggle for the most part through urban sprawl on a four-lane highway.
For Greek officials, the anniversary has provided an unparalleled opportunity to promote the country - even if cutbacks have meant elite marathoners are thin on the ground.
"Every marathon runner dreams of running the classic course," said Kanellopoulos. "The benefits for tourism are already being seen. We estimate that the city of Athens stands to gain as much as €25 million from the race."
More than 12,500 athletes will compete in the marathon. The avidly fit US-born Greek Prime Minister, George Papandreou, is believed to be among the participants.
But after spending most of his year in office striving to keep national bankruptcy at bay he will run only one-third of the course.