Pietro della Vigna

Through his classical education, his ability to speak Latin and his poetic gifts, he then gained the favour of Emperor Frederick II, who made him his secretary, and afterwards judex magnae curiae, councillor, governor of Apulia, prothonotary and chancellor.

But at the First Council of Lyon (1245), which had been summoned by Pope Innocent IV, della Vigna entrusted the defense of his master to the celebrated jurist Taddeo da Suessa, who failed to prevent his condemnation.

His letters, mostly written in the name of the emperor and published by Iselin (Epistolarum libri vi, 2 v., Basel, 1740), contain much valuable information on the history and culture of the 13th century.

It was even stated, probably without any foundation, that they were the authors of the famous work De Tribus Impostoribus, wherein Moses, Jesus and Muhammad are criticised and their teachings are rejected.

Della Vigna reveals his identity to the travelers Dante and Virgil: "I am himself that held both keys of Frederick's heart / to lock and unlock and well I knew / to turn them with so exquisite an art."