Antonio Giordano, called Antonio da Venafro, was born in 1459 in Venafro—about 50 miles North of Naples. He moved to Siena and attended the university there graduating in jurisprudence. In 1488 Venafro was nominated professor of law at the University of Siena. In November 1493 Antonio was nominated Appellate Judge. As such he was arrested by the avant-garde of Charles VIII and obliged to follow them in their march toward Rome. He was freed a few days later only by a direct order of the King himself. A trusted adviser and private secretary of the Lord of Siena, Pandolfo Petrucci, he was named by the latter counselor and prime minister. In the month of October 1502 Venafro represented Pandolfo Petrucci at the Diet of La Magione; and later he went to Imola with Paolo Orsini, where a peace agreement was signed between Cesare Borgia and the 'conspirators' of La Magione represented by Paolo Orsini. Venafro was a statesman of high caliber, appreciated and respected by men such as Guicciardini, Vettori and Machiavelli. In 1515, under constant pressure by Pope Leo X, Antonio left Siena and returned to his native town of Venafro. But a few years later, in 1919, Antonio moved to Naples where he was named a member of the Consiglio Collaterale and professor of jurisprudence at the University of Naples. He died there in 1530.

In chapter 22 of The Prince, where the prince private counselors are discussed, Machiavelli has high praise for Antonio Venafro.