Vanini therefore, fearing the same fate, ran away again to France and headed to Lyon. There, in June 1615, he published "Amphitheatrum", a book against atheism, which he hoped would clear his name with the Roman authorities. A short time later Vanini returned to Paris, where he asked Nuncio Ubaldini to intervene on his behalf with the authorities in Rome. Insufficiently assured, Vanini decided not to return to Italy, and instead cultivated connections with prestigious elements of the French nobility. In 1616, Vanini completed the second of his two works, "De Admirandis", and got it approved by two theologians at the Sorbonne. The work was published in September in Paris. It was dedicated to François de Bassompierre, a powerful man at the court of Marie de' Medici, and was printed by Adrien Périer, a Protestant. The work was immediately successful among those aristocratic circles populated by young spirits who looked with interest to the cultural and scientific innovations that came from Italy. The "De Admirandis" was a summa, lively and brilliant, of the new knowledge, and became a kind of "manifesto" for these cultural free spirits, giving Vanini a chance to stay safe in circles close to the French court. However, a few days after the publication of the work, the two theologians at the Sorbonne who had expressed their approval were presented to the Faculty of Theology in formal session and the outcome was a "de facto" ban on the movement of the text. Now, unwelcome in England, unable to return to Italy and threatened by some circles of French Catholics, Vanini saw his room for manoeuvre shrinking and his chances of finding a stable place in French society failing. Fearing that a court case would be started against him in Paris, he fled and went into hiding at Redon Abbey in Brittany, where Abbott Arthur d'Épinay de Saint-Luc acted as his protector. But other factors gave cause for concern: in April 1617 Concino Concini, favorite of Marie de' Medici, was killed in Paris, giving rise to a wave of hostility to Italian residents at court. In the following months, a mysterious Italian, with a strange name (Pompeo Uciglio) and in possession of great knowledge but an uncertain past, appeared in some cities of Guyenne, then the Languedoc and finally Toulouse. Duke Henri II de Montmorency, protector of "esprits forts" of the time, was the governor of this region and seemed to grant protection to the fugitive, who still continued to keep carefully hidden.