[6][7][verification needed] Renée was married in April 1528 to Ercole II, Duke of Ferrara,[8] eldest son of Alfonso I d'Este and Lucrezia Borgia.

Thus the court that she assembled about her in Ferrara, in the 1530s and 1540s,[9] corresponded to the tradition which the cultivation of science and art implicitly required, including scholars like Bernardo Tasso and Fulvio Pellegrino Morato.

Both their number and influence displeased him; and, besides, he found them too expensive; so he by direct or indirect means secured their dismissal, including the poet Clément Marot.

And while the Curia was urging the duke to put away the French that were suspected of heresy against Catholicism, there came to Ferrara the Protestant theologian John Calvin, whose journey to Italy must have fallen in March and April 1536.

[9] As a result of Renée's patronage, Calvin's opus magnum circulated at the court: the Institutes of the Christian Religion, in two Latin editions (1536, 1539).

[citation needed] Renée was in correspondence with a very large number of Protestants abroad, and with intellectual sympathizers like Vergerio, Camillo Renato, Giulio di Milano [it], and Francis Dryander.

In 1550 and 1551, this court imposed death sentences on Protestant sympathizers (Fanino Fanini [it] of Faenza and Giorgio of Sicily [it]), who were executed by the secular arm.

His power was broken by the death of his nephew Francis II in December 1560, so that Renée was able to provide Protestant worship at her estate Montargis, engaging a capable preacher by application to Calvin.

The Catholic forces left her personally undisturbed at that time, though Catherine de' Medici still sought to move her to retract, a demand which she ignored.