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.
In the meantime the opinion that the property ought to be restored was adopted by the majority of the senate, and this enabled the envoys to prolong their stay, as the consuls required time to provide vehicles for conveying the goods.
They employed their time in consultations with the conspirators, and they insisted on getting a letter, which they were to give to the Tarquins, for without such a guarantee, they argued, how could they be sure that their envoys had not brought back empty promises in a matter of such vast importance?
A letter was accordingly given as a pledge of good faith, and this it was that led to the discovery of the plot.