So passed, peacefully enough, the early weeks of May at the conferences in London. The States’ ambassadors, on the one hand, demanding freedom of navigation and fishery; above all, that the visitation and seizure of their vessels should cease. The English commissioners, on their part, putting forward incompatible claims to the sovereignty of the British seas: the right of exclusive jurisdiction, of guardianship, the right to the fishery. Whether the negotiations would have reached a happy conclusion, as the ambassadors, and apparently also the States-General, believed they would, may only be conjectured. For an event of momentous importance now occurred which swept their labours away and embroiled the two nations in war. On the 19th May, at the very moment when the Dutch ambassadors were conveying their new instructions to the English commissioners, Tromp and Blake were engaged in furious battle in the Straits of Dover about that very matter which the States-General had found to be “so delicate”--the striking of the flag. The long-impending struggle engendered by years of mutual jealousy and commercial rivalry had now come suddenly. The claim of England to the sovereignty of the sea was to be decided, in the words of Sir Philip Meadows, by a longer weapon than a pen. Tromp had put to sea early in May, 1652, with a fleet of forty-two sail, and bearing instructions to prevent the searching of Dutch merchantmen, to protect them against any who interfered with them, and to free them, by force if necessary, if they were captured. He was further told to refrain as far as possible from going on the English coast.[708] On one important point his instructions were defective. He received no definite orders as to how he should act if the fleet of the Commonwealth called upon him to strike his flag. The subject of the salute had been much discussed in the Netherlands, and an opinion was widely held that while their ships would suffer no loss of dignity in striking to a fleet belonging to a crowned head, it was doubtful whether the same homage should be rendered to the ships of a republic like themselves. The question had been definitely raised and fully discussed early in the previous year in connection with Tromp’s expedition to the Scilly Isles, in view of the likelihood of his falling in with the English fleet,--its consideration, indeed, delayed his departure,--but the Government hesitated in coming to a decision, and a general wish was expressed to hear Tromp’s own opinion first. He accordingly prepared a memorandum describing what the States’ ships had done in the past. He said that whenever their men-of-war met at sea a ship of the King of England carrying the flag of an admiral, vice-admiral, or rear-admiral, they struck their admiral’s flag, lowered top-sails, and fired nine, seven, or five guns, the English answering with a like number, and the States’ flag remained struck until the ships separated, when three or one adieu-shots were fired,