Why is the Marathon 42.19 KM ?

We know the modern Marathon is 42.19 kilometers or 26 miles and 385 yards, but what does this strange distance pertain to, why is the Marathon not a whole number of Kilometers or Miles. 

Let us start with the history of the marathon race itself.  Most of us know about the story of how the marathon race started or in fact got its name from, but to refresh one’s memory let’s go back to 490 BC when the Persians were defeated in the great Battle of Marathon, to send out this triumphant message Pheidippides, a Greek messenger ran at a stretch from the battlefield of Marathon to Athens. On arriving and delivering the message of victory he collapsed of exhaustion and died. We will never know the exact distance that Peidippides ran but if we take the approximate route today along the modern Highway between marathon and Athens, it’s around 42.3 Km.

Now taking a look at the distances of modern Marathons I did a comparison between the distances of Olympic Marathon races till the distance got constant.

Olympic marathon distances
Year	Distance (km)	Distance (miles)
1896	40	24.85
1900	40.26	25.02
1904	40	24.85
1906	41.86	26.01
1908	42.195	26.22
1912	40.2	24.98
1920	42.75	26.56
1924 onward	42.195	26.22

When you refer to the above table you will notice that only 1924 onwards are the Marathon race distances a constant 42.195 km. The standard distance of 42.195 was officially set International Amateur Athletic Federation (IAAF) in May 1921 which is based on the 1908 Summer Olympics marathon distance held in London.

Now there is no documentation as to why the marathon distance from this particular Olympic was chosen, but speculation has it that the media had a very large role to play here.

The original distance of the Marathon event in 1908 was 25 miles which was changed to 26 miles on the request of Princess Mary so the race would begin at the Royal Nursery. The distance was further increased to ensure the race would finish in front of the King's seat at the Olympic stadium, bringing the length of the race to 26.22 Miles or 42.195 kms.

Now during the race Dorando Pietri, an Italian runner, who was leading the race, entered the stadium barely able to keep his footing, struggling to finish the race and collapsing a number of times before being helped by a few officials to cross the finish line. This story of a semiconscious man finishing the extended race spread across, the media even started reporting a rumour that Pietri had died in hospital after the race. Such events and articles helped lift up the Marathons image as the ultimate race during those times. 

Now as I mentioned earlier there is no documentation as to why this particular race distance was decided as the official distance but as always a good story always remains in the minds of people, and IAAF might have just decided to use that publicity to keep the race alive.

So here we have it a simple trivial question, but an amazing story about Peidippides and Dorando Pietri, and how their story shaped the distance of our Marathon runs.