Little doubt existed in the minds of the monarch and his ministers that these hostile demonstrations were encouraged, if not suggested, by the secret agents of Philip III of Spain, and the Duke of Savoy, who had been busily engaged some time previously in dissuading the Swiss and Grisons from renewing the alliance which they had formed with Henri III, and which became void at his death. This attempt was, however, frustrated by an offer made to them by Sillery of a million in gold, as payment of the debt still due to them from the French government for their past services; which enormous sum reached them through the hands of the Duc de Biron, to whom, as well as to the memory of his father, the old Maréchal, many of the Switzers were strongly and personally attached. Day by day, also, the King had still more serious cause of apprehension, having ascertained almost beyond a doubt that the Duc de Bouillon, the head of the Huguenot party, who were incensed against Henry for having deserted their faith, was secretly engaged in a treaty with Spain, Savoy, and England, a circumstance rendered doubly dangerous from the fact that the Protestants still held several fortified places in Guienne, Languedoc, and other provinces, which would necessarily, should the negotiation prove successful, be delivered into his hands. There can be no doubt, moreover, that the monarch keenly felt the ingratitude of this noble, whom he had himself raised to the independent sovereignty of the duchy whence he derived his title; but his mortification was increased upon ascertaining that the Maréchal de Biron, who had been one of his most familiar friends, and in whose good-faith and loyalty he had ever placed implicit trust, was also numbered among his enemies, and endeavouring to secure his own personal advancement by betraying his master. No two men could probably have been selected throughout the whole nation more fitted to endanger the stability of the royal authority. Both were marshals of France, and alike celebrated for their talent as military leaders, as well as for their insatiable ambition. Of the two, perhaps, however, the Duc de Bouillon was likely to prove the most formidable enemy to the sovereign; from the fact of his being by far the more able and the more subtle politician, and, moreover, gifted with a caution and judgment which were entirely wanting in the impetuous and reckless Biron. Bouillon, who possessed great influence in the counsels of the Huguenots, was supported by the Duc de la Trémouille,[175] his co-religionist, another leader of the reformed party; and secretly also by the Duc d'Epernon,[176] whose fortunes having greatly deteriorated since the death of Henri III, considered himself harshly treated, and was ready to join every cabal which was formed against that King's successor, although he always avoided any open demonstration of hostility which might tend to compromise his personal safety.