Both Palmerston and Stockmar appear to have been convinced that Talleyrand had prompted his government to protest against the fortress convention.[177] But their suspicions with regard to him seem to have been unfounded. In pursuance of his instructions, in his conversations with Grey and Palmerston, he was bound to employ those arguments most calculated to induce them to make some concessions to the wishes of his Court, but his despatches show that he disapproved strongly of the attitude he was directed to adopt. On December 15, in forwarding a copy of the fortress treaty, the contents of which he knew would be exceedingly displeasing to his government, he told Sébastiani plainly that La Tour-Maubourg's mission to Brussels was largely responsible for the determination of the four Powers to select the fortresses for destruction, without regard to the wishes of France. That affair, moreover, in his opinion, had been managed in a very clumsy fashion. When the government decided to try to arrange a separate understanding with Belgium, it should have conducted its negotiations in the strictest secrecy.[178] Sébastiani, for the reason which has already been explained, was precluded from objecting openly to the exclusion of France from the fortress convention, and was compelled to confine his protests to remonstrances against the selection of Philippeville and Marienburg for demolition. Talleyrand was instructed to contend that the fortifications of these two places, having been erected before 1815, could not be held to fall within the category of works constructed at the expense of the Powers. Furthermore, he was to urge that it was incompatible with the complete independence of Belgium, which France was anxious to see established, that the Powers should specify which fortresses King Leopold was to dismantle.[179] Talleyrand, however, reported that Lord Palmerston was quite unshaken by these arguments. The British minister gave him clearly to understand that La Tour-Maubourg's proceedings at Brussels had impressed him most unfavourably. At the same time, pointing out that Philippeville and Marienburg were the fortresses in closest proximity to the frontier of France, he hinted that the French government must have some secret reason for objecting to their demolition. "Nevertheless," reported Talleyrand, "I still believe that he is well disposed towards us. He is, however, in a difficult position as regards the Commons. . . . We must bring pressure to bear upon the Belgians."[180] Sébastiani's fears that the policy of the Powers aimed at the re-establishment of the Holy Alliance, were, he assured him, in language no less emphatic than that used by Granville in Paris, entirely without foundation. Far too much importance, he urged, was attached to the fortress convention. The King's government, in his opinion, would be well advised to accept it, and to declare publicly that its provisions were in harmony with the protocol of April 17.