[Footnote 6:  In all these naval battles we have followed Hume and the English historians as to dates, which, in almost every instance, are strangely at variance with those given by the Dutch writers.]

The king of France hastened forward in this crisis to the assistance of the republic and De Witt, by a deep stroke of policy, amused the English with negotiation while a powerful fleet was fitted out.  It suddenly appeared in the Thames, under the command of De Ruyter, and all England was thrown into consternation.  The Dutch took Sheerness, and burned many ships of war; almost insulting the capital itself in their predatory incursion.  Had the French power joined that of the Provinces at this time, and invaded England, the most fatal results to that kingdom might have taken place.  But the alarm soon subsided with the disappearance of the hostile fleet; and the signing the peace of Breda, on the 10th of July, 1667, extricated Charles from his present difficulties.  The island of Polerone was restored to the Dutch, and the point of maritime superiority was, on this occasion, undoubtedly theirs.

While Holland was preparing to indulge in the luxury of national repose, the death of Philip IV. of Spain, and the startling ambition of Louis XIV., brought war once more to their very doors, and soon even forced it across the threshold of the republic.  The king of France, setting at naught his solemn renunciation at the peace of the Pyrenees of all claims to any part of the Spanish territories in right of his wife, who was daughter of the late king, found excellent reasons (for his own satisfaction) to invade a material portion of that declining monarchy.  Well prepared by the financial and military foresight of Colbert for his great design, he suddenly poured a powerful army, under Turenne, into Brabant and Flanders; quickly overran and took possession of these provinces; and, in the space of three weeks, added Franche-Comte to his conquests.  Europe was in universal alarm at these unexpected measures; and no state felt more terror than the republic of the United Provinces.  The interest of all countries seemed now to require a coalition against the power which had abandoned the House of Austria only to settle on France.  The first measure to this effect was the signing of the triple league between Holland, Sweden, and England, at The Hague, on the 13th of January, 1668.  But this proved to be one of the most futile confederations on record.  Charles, with almost unheard-of perfidy throughout the transaction, fell in with the designs of his pernicious, and on this occasion purchased, cabinet, called the Cabal; and he entered into a secret treaty with France, in the very teeth of his other engagements.  Sweden was dissuaded from the league by the arguments of the French ministers; and Holland in a short time found itself involved in a double war with its late allies.