The Dutch had agreed to acknowledge the English flag in the British seas, but the English claimed it should be saluted on all. In 1663, De Ruyter and Admiral Lawson had almost come to cannon shots in the Mediterranean over salutes claimed for the flag, and recriminations and searchings had extended to the waters of the far East Indies, where the Dutch, who had taken the Cape of Good Hope from the Portuguese, were competing with the English ships for the merchant trade. Soon, under Charles II., another Dutch war (1665-67) blazed out, during which De Ruyter sailed up the Thames to Gravesend and destroyed the ships at Chatham and in the Medway, and London was for the first time startled by the sound of an enemy's guns. Again the success was but temporary, for at the close of the war New Amsterdam in America, and with it the command of the Hudson River, was ceded to the English. The name of the new territory then obtained was changed to New York, in honour of the Duke of York, the King's brother, which English and royal name it still retains, although now forming the principal maritime city of the Republic of the United States. With the booty came, in the articles of peace, the old-time ascription of sovereignty to the British flag. It was again agreed by one of the articles of the treaty: "That the ships and vessels of the so United Provinces, as well men-of-war as others, meeting any man-of-war of the said King of Great Britain in the British seas, shall strike their flag and lore the topsail in such manner as the same hath been formerly observed in any times whatsoever."[55] [55] Treaty of Breda, 1667. But the rivalry was too intense to continue much longer without coming to a definite climax. The "command" foreseen by Raleigh was at stake. Both nations had the maritime instinct, and both the genius of colonizing power, so that one or the other of them must give place and leave to the survivor the supreme possession of all that this command implied. Formal negotiations between the governments had been rife, but the vital test was the supremacy due to the flag. An English royal yacht was ordered to sail through the Dutch men-of-war in the channel and to fire on them if they did not strike their flags. An ultimatum was sent summoning Holland to acknowledge the right of the English crown to the sovereignty of the British seas and to order its fleets to lower their flags to the smallest English man-of-war.[56] [56] Mahan. Thus the third and final war came on in 1672 and continued until 1674.