IX. He was now at the height of his glory by the prodigious success of his admirable book _Of the rights of war and peace_, which a celebrated writer[147] justly styles a master-piece. He began it in 1623 at Balagni, and in 1625 it was published at Paris. It was the famous Nicholas Peyresc, the Mecaenas of his age and the ornament of Provence, who engaged Grotius to handle this subject. He writes to that worthy magistrate, Jan. 11th, 1624. "I go on with my work _Of the law of nations_: if it may be of use to the world it is to you posterity will owe the obligation, since you made me undertake it, and assisted me in it." In the preliminary discourse he sets forth his motives for treating this subject. "Many strong reasons determined me to write at this time. I have observed in all parts of the Christian world such an unbridled licentiousness with regard to war as the most barbarous nations might blush at: they fly to arms without reason, or on frivolous pretexts; and when they have them once in their hands they trample on all laws human and divine, as if from that time they were authorised, and firmly resolved to stick at no crime." Thus it was from a principle of humanity that he composed this great work; and, as he writes to Crellius[148], to shew how unbecoming it was for a Christian and a reasonable man, to make war from caprice: which was too much practised. In the dedication of this book to the King the author observes, that Lewis XIII. like a propitious constellation, not satisfied with relieving the misfortunes of princes and protecting nations, had graciously supported him under his afflictions. He presented his book to the King and the principal nobility; who, he writes to his brother[149], received it very graciously, but made him no return. He imagined it was because he had handled in it several points of divinity: and the court would not shew any favour to heterodox works, in which such questions were discussed: but the favourable reception it met with from all Europe sufficiently made up this loss. It will not be expected that we should make an analysis or enter into an examination of the treatise _On the rights of war and peace_: that would be a subject for a large work. We shall only observe that those who would study the law of nations cannot read this book too often: they will find in it the most agreeable learning joined to the strongest reasoning. The whole is not equally correct: but what large work is not liable to the same censure? Besides, we must consider that it has the glory of being original in its kind[150], and the first treatise that reduced into a system the most excellent and useful of all sciences. It is divided into three books; to which is prefixed a preliminary discourse treating of the certainty of law in general, and containing a plan of the work.