The identification of the month of the year 490 B.C., in which the ancient Marathon runner “flied” to bring the victorious message to Athens, is directly connected with the precise dating of he Marathon battle. Calculating on the basis of the Spartan calendar which commenced on the first new moon after the autumnal equinox, and speculating that the battle was conducted in the month of Karneios as well as the Spartan year 491/490 Included an inserted month, we find out that Karneios, which regularly is the eleventh month of the Spartan calendar, has become, owing to the insertion, the twelfth month. Therefore, it started on
27 August and not on 26 July, as Professor D.W. Olson and his team have proposed. As regards the Attic calendar, the summer solstice of the year 490 B.C. is astronomically observed at 04.16 hours of 29 June and the new moon of the month at 02.39 hours of 27 June. However, this moon was observable at 21:45 hours of 29 June. Therefore, this date follows the summer solstice and must be identified with the first moon of the Attic year 90/489 and not to the month Meageitnion, the second month of the Attic calendar, begins on 28 July, and Boedromion, he third month, on 27 August, 490 B.C. As a result, the month Karnelos of the Spartan calendar corresponds to the month Boedromion of the Attic year 490/489 and not to the month Metageitnion as Professor A. Boeckh has suggested. Thus, according to the aforementioned calculations, we propose the following dating:
Karn./Boed. Sept. 490 B.C.
14 9/10 full moon
15 10/11 end of Karneian Festival
16 11/12 departure of the Lacedaemonians from Sparta
7 12/13 Marathon battle, dispatching of messenger to Athens
18 13/14 arrival of Lacedaemonians to Athens
Conclusively, according to both the Attic and the Spartan calendars, the ancient Marathon runner run in September of 490 B.C.