Cardinal Thomas Cajetan, commonly Tommaso de Vio or Thomas de Vio, had helped in drawing up the bill of excommunication against Luther in 1519.

De Vio has been employed in several other negotiations and transactions, being as able in business as in letters.

In conjunction with Cardinal Giulio de' Medici in the conclave of 1521‑1522, he had secured the election of Adrian Boeyens, bishop of Tortosa, as Adrian VI.

He has retained influence under Clement VII, suffered a short term of imprisonment after the storming of Rome by the Constable of Bourbon and by Frundsberg (1527), had retired to his bishopric for a few years, and, returning to Rome in 1530, had assumed his old position of influence about the person of Clement, in whose behalf he has written the decision rejecting the appeal for divorce from Catharine of Aragon made by Henry VIII of England.

Nominated by Clement VII a member of the committee of cardinals appointed to report on the "Nuremberg Recess", he has recommended, in opposition to the majority, certain concessions to the Lutherans, notably the marriage of the clergy as in the Greek Church, and communion in both kinds according to the decision of the council of Basel.

Cardinal De Vio dies in Rome on Augusti 9,1534.