The question of the nature of the coercion which should be applied to the Belgians, should they persist in laying claim to Luxemburg, was not easy of solution. The Grand Duchy formed part of the Germanic Confederation, and therefore it should have devolved upon the Federal Diet to take the steps required for restoring the sovereignty of the King of the Netherlands. Sébastiani, however, deprecated the idea of employing German troops for the purpose of enforcing the decisions of the conference. But on the understanding that both the strength of the contingent, which was to enter Belgium, and the date on which the military operations were to begin should be settled by the five Powers, the French government withdrew its objections.[125] Prince Leopold, at the same time, informed the members of the deputation, who had come to London to offer him the crown of Belgium, that he could not listen to their proposals, until the national congress should have accepted the conditions of the 11th and 12th protocols. No persuasion could move him from this resolution which met with the full approval of the British government. Talleyrand, however, as a compromise appears to have suggested the plan of proposing to the King of the Netherlands the cession of the province of Luxemburg, without the fortress, in return for a pecuniary indemnity.[126] This solution of the difficulty was considered so practicable by Lord Ponsonby that, upon his own responsibility, he left Brussels and journeyed to London to urge its adoption. The conference, in consequence of his representations, agreed to open negotiations with the King of the Netherlands for the purchase of Luxemburg and for "so much of the province of Limburg as would connect Maëstricht with North Brabant."[127] But when June 1, the date which had been assigned as that on which the Belgians must signify their agreement to _les bases de separation_, went by without a favourable answer having been received from Brussels, the conference withdrew Ponsonby and decided to resort to measures of coercion. The action of the national congress, in electing Prince Leopold King of the Belgians on June 4, had no effect upon the decision of the Powers. "It has been used," wrote Palmerston, "as a fresh opportunity for putting forward pretensions to portions of the territory of the King of Holland and by implication, at least, of repeating their determination to gain possession of them by force."[128]