It was not till the 22d of February, 1665, that war was formally declared against the Dutch; but many previous acts of hostility had taken place in expeditions against their settlements on the coast of Africa and in America, which were retaliated by De Ruyter with vigor and success. The Dutch used every possible means of avoiding the last extremities. De Witt employed all the powers of his great capacity to avert the evil of war; but nothing could finally prevent it, and the sea was once more to witness the conflict between those who claimed its sovereignty. A great battle was fought on the 31st of June. The duke of York, afterward James II., commanded the British fleet, and had under him the earl of Sandwich and Prince Rupert. The Dutch were led on by Opdam; and the victory was decided in favor of the English by the blowing up of that admiral's ship, with himself and his whole crew. The loss of the Dutch was altogether nineteen ships. De Witt the pensionary then took in person the command of the fleet, which was soon equipped; and he gave a high proof of the adaptation of genius to a pursuit previously unknown, by the rapid knowledge and the practical improvements he introduced into some of the most intricate branches of naval tactics. Immense efforts were now made by England, but with a very questionable policy, to induce Louis XIV. to join in the war. Charles offered to allow of his acquiring the whole of the Spanish Netherlands, provided he would leave him without interruption to destroy the Dutch navy (and, consequently, their commerce), in the by no means certain expectation that its advantages would all fall to the share of England. But the king of France resolved to support the republic. The king of Denmark, too, formed an alliance with them, after a series of the most strange tergiversations. Spain, reduced to feebleness, and menaced with invasion by France, showed no alacrity to meet Charles's overtures for an offensive treaty. Van Galen, bishop of Munster, a restless prelate, was the only ally he could acquire. This bishop, at the head of a tumultuous force of twenty thousand men, penetrated into Friesland; but six thousand French were despatched by Louis to the assistance of the republic, and this impotent invasion was easily repelled. The republic, encouraged by all these favorable circumstances, resolved to put forward its utmost energies. Internal discords were once more appeased; the harbors were crowded with merchant ships; the young Prince of Orange had put himself under the tuition of the states of Holland and of De Witt, who faithfully executed his trust; and De Ruyter was ready to lead on the fleet. The English, in spite of the dreadful calamity of the great fire of London, the plague which desolated the city, and a declaration of war on the part of France, prepared boldly for the shock.