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.
During the secessions of the plebs in the old days a nail had been driven in by the Dictator, and by this act of expiation men's minds, disordered by civil strife, had been restored to sanity. A resolution was passed accordingly, that a Dictator should be appointed to drive in the nail.
Cnaeus Quinctilius was appointed and named L. Valerius as his Master of the Horse. After the nail was driven in they resigned office.