[384] Ep. 1320. p. 598. [385] Ep. 1319. p. 597. [386] Ep. 1328. p. 601. [387] Ep. 1333 p. 613. [388] Ep. 1337. p. 607. Puffendorf, l. 12. sec. 52. [389] Ep. 1338. p. 607. [390] Ep. 1344. p. 609. [391] Ep. 1548. p. 611. VIII. Grotius was at this time engaged in another very delicate negotiation at the Court of France. Marshal Horn, the High Chancellor's son-in-law, had been taken at the battle of Nordlinguen, and Sweden was most desirous to recover her General. The famous John de Vert was at the same time prisoner at Vincennes[392]: nothing seemed more natural or easy than the exchange of these two great Captains: it was obstructed, however, by two considerable difficulties. The Duke of Weymar pretended that John de Vert was his Prisoner, and that he only sent him into France to be kept there till he should redemand him. Besides, the French Court were afraid that Marshal Horn's return would be rather hurtful, than advantageous to the common cause: there was no longer any employment for the Marshal in the army, and as he was supported by the credit of his father-in-law, his return to it might occasion a dangerous division, the consequences whereof were to be apprehended even by France herself. Grotius[393] nevertheless was ordered to solicit the King in favour of this exchange: he spoke of it first to Bullion[394], who frankly promised to do all in his power for Sweden in the affair. He afterwards spoke of it to the King at an audience in the beginning of November, 1639; an account of which he sends to the Queen, in a letter of the 9th of November. He tells her, that, having pressed the King to procure the Marshal's liberty, Lewis discovered great readiness to do it, and promised to propose it in council. The Ambassador, to engage the King more warmly for this exchange, represented to his Majesty, that the late Duke of Weymar designed the generals John de Vert and Enkefort to be exchanged for Marshal Horn: that the Prince thought his glory concerned in making this exchange; that he had mentioned it to the Queen of Sweden; and often written to his Majesty about it, and several times employed others to solicit it, and that he died in these sentiments. Marshal Horn's liberty could not be obtained without the consent of another Prince, the Duke of Bavaria, with whom he was a prisoner. That Prince, being spoke to, readily gave his consent to the exchange. Marshal Horn wrote this to Grotius, in a letter delivered to him by John de Vert: and the Ambassador immediately wrote to the High Chancellor, May 16, 1640, that he thought the Queen should make new instances by letter to the King, and give him [Grotius] fresh orders on the subject.