When the affair was advanced thus far, Estrades lost no time in forwarding an account of it to Lewis, to whom, as he says himself, he had not before ventured to write upon the subject, because at first he despaired of being able to bring the intrigue to bear: but he now thought it in so good a train, that upon receiving the approval of his proceedings from Lewis, he could almost answer for its success. The letter of Estrades was accompanied by a schedule, containing the demands of the Duke of Mantua, and by a letter from Matthioli, also addressed to Lewis, in which he offers to devote himself to his service, to strive to detach his master, the Duke of Mantua, from the Austrian interest, and insinuates very plainly his wish and intention of selling him and his fortress of Casale to the French Monarch; whom, he says, he "regards and reveres as a _Demigod_."[22] To these protestations Lewis returned, as was natural, a very civil answer;[23] generally promising his protection and favour to Matthioli.
On the 24th of December of the same year, Estrades[24] writes to M. de Pomponne,[25] (then one of the Secretaries of State), to inform him of a discovery he has made from the Duke of Mantua himself, that the Austrian party have determined, in case any French troops should arrive in Italy, and that the Duke of Mantua should manifest any disposition of favouring them, to seize upon Casale and Mantua. He therefore adds that the Duke, though thoroughly well-disposed towards the French interests, cannot take any active part in their favour, unless Lewis will send into Italy a sufficient force to secure Casale and the rest of the Duke's territories from the attempts of the House of Austria. He subsequently seems to hint his fear that the life of the Duke of Mantua may be made away with by the Austrians, in order the more easily to possess themselves of his territories. "We must besides, Sir, consider that the Duke of Guastalla[26] being the nearest relation of the Duke of Mantua, as well as his heir, there would be danger that, if the Duchess,[27] his daughter, who is very ill and has no children, should die, some _misfortune_ might happen to the Duke of Mantua, which would assure his territories to the Spanish Nobleman, who has married the second daughter[28] of the Duke of Guastalla, and whose marriage the Spaniards, _doubtless with this view_, made up at Vienna by means of Don Vincent."[29]