Philip was bound by his promises to send to Belgium a prince of the blood. His choice of Archduke Ernest, son of Maximilian II, was, however, an unhappy one, as the weak prince was entirely dominated by his Spanish general, Fuentes, brother-in-law of the Duke of Alba. The country suffered, at the time, from the combined attacks of Maurice of Nassau and of Henry IV of France. After the death of Archduke Ernest, Philip chose as governor-general the former's younger brother, Archduke Albert, who had distinguished himself as Viceroy of Portugal. He arrived just in time, in 1596, to relieve the situation by the taking of Calais. This success was short-lived, and by the treaty of Vervins (May 2, 1597) Philip was obliged to restore Calais to France, together with the Vermandois and part of Picardy. The next year the king negotiated the marriage of his daughter Isabella with Archduke Albert. He died on September 13, 1598, before the marriage could be celebrated. Had Philip II come to this last determination willingly, the future of the Low Countries, at least of the Southern provinces, might still have been saved. But this last act of the sovereign whose rule had been so fatal to the Netherlands proved as disappointing as the others. While he wrote in the act of cession that "the greatest happiness which might occur to a country is to be governed under the eyes and in the presence of its natural prince and lord," he almost annihilated this very wise concession to Belgian aspirations by adding stringent restrictions. The inhabitants of the Low Countries were not allowed to trade with the Indies; in the eventuality of the Infanta Isabella having no children, the provinces would return to the crown. Besides, the act contained some secret clauses according to which the new sovereigns undertook to obey all orders received from Madrid and to maintain Spanish garrisons in the principal towns. The Spanish king reserved to himself the right to re-annex the Low Countries in any case, under certain circumstances. This half-hearted arrangement, besides placing the archduke in a false position in his relations with his subjects, deprived him of all initiative in foreign matters. In fact, in spite of his sincere attempts to shake off Spanish influence, he enjoyed less independence than some former governors, like Margaret of Austria.