Grotius had either been misinformed, or the Cardinal changed his language: for the former writes to his brother[665], March 24, 1642, "As Cardinal Richelieu speaks differently from what he did some time ago about the peace of the churches, I am afraid this change conceals some ill design against the Reformed." Grotius, finding at length that the project of a coalition was impracticable without the approbation of the Catholics, contracted an intimacy with Father Petau, to whom he communicated all his works relating to religion and the reconciliation of the churches. In a letter of the 3d of December, 1640, he desires him to send him his remarks on his works, "That, says he, by your assistance I may add, suppress, or correct, as shall be most necessary for promoting truth and peace. Would to God that I had as much genius and learning as some others: I would accomplish what it is great barely to attempt." He communicated to Father Petau the manuscript of his answer to Rivetus[666], desiring him to point out what was not agreeable to truth, or had not a tendency to promote peace. "I am resolved, says he, to publish my answer as soon as I have your opinion, to which I pay great regard." Father Petau gives us the history of his acquaintance with Grotius, in his XIIth letter[667]. "I had, says he, a great desire to see and converse with him; we have been long together, and very intimate. He is, as far as I can judge, a good man, and of great candour. I do not think him far from becoming a Catholic, after, the example of Holstenius, as you hoped: I shall neglect nothing in my power to reconcile him to Christ, and put him in the way of salvation." Father Petau mentions him again in another letter, written to Cardinal Francis Barberinus[668]. His Eminence had applied to that learned Jesuit for information in what state Grotius had left, at his death, his work on the Antiquities of Sweden. Father Petau makes him this answer. "I had some connection with Hugo Grotius, and I wish I could say he is now happy. Our love to learning began our acquaintance, which I kept up in hopes of being useful to him. Accordingly I saw him often, and he also visited me, and wrote to me frequently." He concludes with assuring the Cardinal, that he would enquire of his widow about his work relating to Sweden.