He ought to have determined himself long before.  Convinced at last that he must lay aside all thoughts of returning into Holland, he yielded to the pressing instances of the High Chancellor of Sweden, who wanted to employ him in affairs of importance.  Grotius gave the preference more readily to this Minister, the greatest man perhaps of his age, because he followed Gustavus’s plan, for whom Grotius had a singular veneration:  in January, 1628[198], he speaks of him as a Prince whose greatness of soul and knowledge in civil and military matters placed him above every other.  March 12, in the same year, he writes to his brother[199], that on every occasion he would do all in his power to serve such a virtuous Monarch.  On the 28th of April following, he congratulates Camerarius[200], whose father was Ambassador from Sweden, on his serving a Prince who merited every commendation.  “The whole universe will not furnish his equal in virtue[201].  Men of the greatest merit in this country think the brilliancy of this Prince’s actions and virtues must strike even envy dumb.  Happy are they who are under the protection of so great a King.  He proves the possibility of what appeared incredible in the great men of antiquity:  he is a witness who gives evidence in their favour:  he will serve for a master to posterity; and the best lessons in the art of war will be taken from his history.  He is no less eminent as a warrior, than as a statesman[202]; and in him is found all that makes a great King.  He is the wisest Monarch now reigning, and knows how to improve every opportunity to the best advantage, not only when the injustice of his enemies obliges him to have recourse to arms, but also when he is allowed to enjoy the blessings of peace.”  The Letters, in which he expresses his profound esteem for the Great Gustavus, were all written before the month of June, 1630, whilst he resided at Paris and had no thought of entering into the Swedish service.

Gustavus had sent to Paris Benedict Oxenstiern, a relation of the High Chancellor, to bring to a final conclusion the treaty between France and Sweden.  This Minister made acquaintance with Grotius, and in a short time conceived such a high esteem for him, that he resolved to employ his credit to draw him to his Master’s court.  A report of this spread in Holland; and William Grotius wrote about it to his brother, who made answer, Feb. 6, 1632, That these reports were without foundation; that, besides, he had an aversion to following an army.  It was said that King Gustavus intended to employ him at the Court of France; and he answered his brother on this subject, Feb. 18, 1632, That if this Monarch would nominate him his Ambassador, with a proper salary for the decent support of that dignity, the proposal would merit his regard.

This Prince, who was certainly the greatest Captain of his age, had at the same time an affection for men of learning.  The reading of the treatise Of the Rights of War and Peace gave him the highest opinion of its author, whom he regarded as an original genius[203]; and he was persuaded that one who wrote so well on the Law of Nations must be an able Statesman.  He resolved to gain him, and to employ him in some embassy.  The High Chancellor of Sweden, who was of the same opinion with his Master, was Grotius’s patron at Court.