Ab urbe condita
Titus Livius (Livy)
Livy. History of Rome, Volumes 1-2. Roberts, Canon, Rev, translator. London, New York: J. M. Dent and Sons; E. P. Dutton and Co., 1912.
Since then it is of supreme importance in human affairs what things men do under divine favour and what they do against the divine will, he well assured that, if in your former wars you were fighting against the gods even more than against men, in this war which is impending you will have the gods themselves to lead you.”
After uttering this prediction, which proved to he as true as it was reassuring, he took the field and, keeping his movements as secret as possible, fixed his camp in the neighbourhood of Caudium.
From there he sent ten soldiers disguised as shepherds to Calatia, where he understood that the Roman consuls were encamped, with instructions to pasture some cattle in different directions near the Roman outposts.
When they fell in with any foraging parties they were all to tell the same story, and say that the Samnite legions were in Apulia investing Luceria with their whole force and that its capture was imminent.
This rumour had purposely been spread before and had already reached the ears of the Romans; the captured shepherds confirmed their belief in it, especially as their statements all tallied.