In Book 8 Part 98, Herodotus writes:
... Than this system of messengers there is nothing of mortal origin that is quicker. This is how the Persians arranged it: they say that for as many days as the whole journey consists in, that many horses and men are stationed at intervals of a day's journey, one horse and one man assigned to each day. And him neither snow nor rain nor heat nor night holds back for the accomplishment of the course that has been assigned to him, as quickly as he may. The first that runs hands on what he had been given to the second, and the second to the third, and from there what is transmitted passes clean through, from hand to hand, to its end ...
(from the David Greene translation)
TopicLiterature - Datetag20070516