He received information of this from one of his friends.

The foul calumny stung him with indignation; and though he did not think it deserved to be confuted, he wrote of it to the Lord Keeper, and in a letter on this subject to Du Maurier he calls God to witness, that he had never seen any of the Spanish Ambassadors, and that there was not a man in the United Provinces who wished better to his Country.
He had an offer of being Professor of Law in Denmark[157], but the character of the Danes made him averse to that country: besides, he thought the places he had already filled did not permit him to become a Professor in a College; as to the Salary, he was satisfied with it.
While he was in suspense what he should do, the King nominated Cardinal Richelieu Prime Minister.

His Eminence had a mind to be particularly acquainted with Grotius, and asked him to come to his house at Limours: he was introduced by Marshal de Fiat.

We are ignorant of what passed at this interview: all we know is that the Cardinal, purposing to restore the navy and trade of the nation, talked of these matters to Grotius; who acquainted his brother with his visit to the Cardinal in a letter dated May 21, 1626.
It is highly probable the Cardinal proposed to Grotius to devote himself entirely to him: that minister protected none but such as professed an absolute submission to his will in all things.

He gave Grotius so great hopes that he thought he might write to his father, "If I would forget my country, and devote myself wholly to France, there is nothing which I might not expect." But there is room to imagine the proposals made to him by the Cardinal were inconsistent with his principles; and he was not a man to act against his conscience on any consideration.