He received the agreeable account, that the pieces he had written to promote the coalition were approved of in Denmark, Sweden, England, Germany, and Poland.

He imagined several Catholics entered into his views.  Divers doctors of the Sorbonne, he said[661], thanked him for the remarks he wrote on the Consultation of Cassander.  “The ablest men among the Catholics think what I have done, he tells his brother[662], is written with great freedom and moderation, and approve of it.”

“We ought not, he says in another letter[663], to regard only the present age, but posterity also:  yet I find some people who think they shall live to see the union restored.”

He imagined his manner of handling the controversy was approved of by the ablest men of the Romish Communion, and even at Rome because there were most great men in that city.

For some time he entertained hopes that Cardinal Richelieu would favour him:  Jan. 19, 1641, he writes thus to his brother[664]:  “When my book is published, many Protestants will see that the reconciliation of the Churches is easier than they imagined:  for the principal basis of the Reformation may subsist with the Pope’s consent, provided the affair be managed with mildness and without giving him offence.  I write this on good grounds:  Cardinal Richelieu thinks the thing will succeed:  he has said so to several.”

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.”