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.
It was about four o'clock in the afternoon when the general ordered the troops to take food, and instructed them to remain under arms and in readiness at what- ever hour he gave the signal, whether by day or by night.