The intercepted letters of the Comte d'Auvergne having also implicated his stepfather M. d'Entragues, and his sister Madame de Verneuil, both were subsequently arrested; the former by the Provost Defunctis[267] in his castle of Marcoussis, and the latter at her residence in the Faubourg St. Germain; while her children were taken from her, and sent, under a proper escort, to the palace of St. Germain-en-Laye. So important did it, moreover, appear to the French ministers to ascertain the exact extent of the conspiracy, that the Provost was accompanied to Marcoussis by M. de Loménie, in order that a search might be instituted upon the premises; the result of which tended to prove, beyond all possibility of doubt, that the original engagement delivered by the father of the Marquise to the sovereign had, in fact, not been restored, but had been skilfully copied by some able pen; while the importance which was still attached to the real document by the family of Madame de Verneuil may be gathered from the fact that it was discovered by the Secretary of State in a glass bottle, carefully sealed and enclosed within a second, which was laid upon a heap of cotton and built up in a wall of one of the apartments. Nor was this the only object of importance found in the possession of M. d'Entragues; as, together with the promise of marriage which he had professed to restore to the King, M. de Loménie likewise discovered, secreted with equal care, sundry letters, the treaty between Philip of Spain and the conspirators, and the cypher which had been employed in their correspondence.[268] From these documents it was ascertained that the King of Spain had stipulated on oath that, on the condition of Madame de Verneuil confiding her son to his guardianship, he should be immediately recognized as Dauphin of France, and heir to the throne of that kingdom; while five fortresses in the territory of Portugal should be placed at his disposal, and subjected to his authority, as places of refuge should such a precaution become necessary. A similar provision was, moreover, made for the Marquise herself; and an income amounting to twenty thousand pounds English was also promised to the quasi-Prince for the support of his household. Nor was this domestic arrangement by any means the most important feature of the conspiracy, as appointments, both civil and military, involving considerable pecuniary advantages, were also promised to the Comte d'Auvergne and his stepfather; and a simultaneous invasion was arranged by the Duke of Savoy in Provence, the Condé de Fuentes[269] in Burgundy, and Spinola[270] in Champagne.