By the end of 1658 the diplomacy of Mazarin had succeeded in bringing about the complete isolation of Spain. She had been crushed by Turenne in the battle of the Dunes, and in the Milanese she was being driven to bay by the united strength of France, Modena and Savoy. Alexander VII., albeit he had attained to the tiara by Spanish influence, was favourably inclined towards Louis XIV. The League of the Rhine (Aug. 14, 1658) had raised a power in the Empire ready to turn at once against the Emperor should he display the slightest intention of coming to the assistance of Spain in the Netherlands. Deprived thus of all support in
Central Europe, Spain had but little prospect of being able to withstand an Anglo-French coalition. There was nothing for it but to submit. A suspension of hostilities between France, England, and Spain was signed as a preliminary to definitive negotiations. The plan of marriage with the Infanta threatened for an instant to fall through owing to the infatuation of Louis XIV. for Maria Mancini, Mazarin's niece, but the latter was unhesitatingly sacrificed by Mazarin to the political interests of France. The articles of peace were threshed out from August i3th to November 7, 1659, by Mazarin and Luis de Haro in person on the Ile des Faisans in the Bidassoa river, the frontier of France and Spain. By this treaty France triumphed over the Haps- burgs in Spain as she had already triumphed over the Hapsburgs in Austria in the Peace of Westphalia (1648), and it was by this treaty that the pre-eminence of France in Europe was established. The treaty is considered to be the nee plus ultra of seventeenth-century diplomacy.