When the conquest of England, in 1066, had been completely effected by the Norman forces, the shores on each side of the "narrow seas" between England and Normandy were combined under the rule of William the Conqueror, communication by water increased between the two portions of his realm, and the maritime interests of the people were greatly extended and established.
Richard I. showed England to the other nations, during the Crusades, as a strong maritime power. King John followed in his footsteps, and in 1200, the second year of his reign, issued his declaration directing that ships of all other nations must honour his Royal flag:
"If any lieutenant of the King's fleet in any naval expedition, do meet with on the sea any ship or vessels, laden or unladen, that will not vail and lower their sails at the command of the Lieutenant of the King or the King's Admiral, but shall fight with them of the fleet, such, if taken, shall be reported as enemies, and the vessels and goods shall be seized and forfeited as the goods of enemies."
The supremacy which King John thus claimed, his successors afterwards maintained and extended, so that under Edward I., Spain, Germany, Holland, Denmark, and Norway, being all the other nations, except France, which bordered on the adjacent seas, joined in according to England "possession of the sovereignty of the English seas and the Isles therein,"[30] together with admission of the right which the English had of maintaining sovereign guard over these seas, and over all the ships of other Dominions, as well as their own, which might be passing through them.
Edward II. was given, in 1320, the title of "Lord of the Seas."[31]
Edward III., himself a sailor-king and commander of his fleets, was fully imbued with the force of the Alfred maxim, so that when invasion threatened England he said, "he deemed it better with a strong hand to go seek the enemy in his own country than wait ignobly at home for the threatened danger."[32] Putting his maxim into action he led his fleet across the Channel, and his victory over the French fleet at Sluys, off Flanders, on the 24th June, 1340, was the Trafalgar of its day, and the resulting supremacy of the English Jack on the narrow seas enabled him to land his forces on the foreign shores, when he subsequently invaded France to establish his claim to the French throne.
The prowess of himself and of his seamen in their victory over the French and Spanish fleets won for Edward the proud title of "King of the Seas," in token of which he was represented upon his gold coinage standing in a ship "full royally apparelled."[33]
During the Wars of the Roses less attention was given by the nation to maritime matters, and while the English were so busily engaged in fighting amongst themselves, the Dutch of the Netherlands, under the Duke of Burgundy, developed a large carrying trade, and so increased their fleets that, in 1485, at the accession of Henry VII., they had become a formidable shipping rival of England, and were a thorn in the side of France. Over the ships of the French the Dutch so lorded it on the narrow seas that, to quote Philip de Commines, their
"navy was so mighty and strong, that no man durst stir in these narrow seas for fear of it making war upon the King of France's subjects and threatening them everywhere."