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.
They felt that it would be a disgrace to the whole Roman nation, and especially to their house, if, while the male issue of Ancus was still,alive, the sovereignty of Rome should be open not only to foreigners but even to slaves. They determined, therefore, to repel that insult by the sword.
But it was on Tarquin rather than on Servius that they sought to avenge their wrongs; if the king were left alive he would be able to deal more summary vengeance than an ordinary citizen, and in the event of Servius being killed, the king would certainly make any one else whom he chose for a son-in-law heir to the crown. These considerations decided them to form a plot against the king's life.
Two shepherds, perfect desperadoes, were selected for the deed. They appeared in the vestibule of the palace, each with his usual implement, and by pretending to have a violent and outrageous quarrel, they attracted the attention of all the royal guards. Then, as they both began to appeal to the king, and their clamour had penetrated within the palace, they were summoned before the king.