William's victory at the Battle of Hastings was a critical turning point in the history of England, of Europe, and of the world.

With the introduction of the Norman culture into England, the Norman and Anglo-Saxon cultures merged and a new English culture emerged. The Normans introduced feudal society to England. Castles began to spring up all over the country. In the beginning, most of these were of wood but as the years and centuries progressed they were built more substantially of stone.

Although William was now King of England, he was also Duke of Normandy and therefore had to maintain his island kingdom and his Continental dukedom against aggression. The possession of Normandy by the English kings was to make England a major European power. With the advent of the Plantagenet kings in the 12th century, the Continental possessions would grow to astounding proportions as the English kings entered into exceptionally advantageous marriages. At the height of England's power in medieval Europe, the English kings possessed more land in what is now present day France than did the French kings, to whom the English kings owed homage for these dukedoms and whatever.

The demise of the Saxon dynasty in England changed the country's posture among nations. Before the Norman conquest, the English only fought with other nations to protect themselves from incursion and invasion. They really had no interest in anything beyond their own island. After the conquest, England had special interests on the Continent and became deeply involved in European politics. The Normans imported their culture into England and inherent in this was their propensity for war; which was not limited to war between themselves as with the Anglo-Saxons.

The Normans introduced the bow into the English army. Prior to the Conquest, it was used very little by the Anglo-Saxons and never en masse. The bow that the Normans brought to England was about four feet long. In a comparatively short time, the English developed the famous longbow, which was about 6 feet in length and tremendously powerful. It turned out that the English were natural bowman. The longbowmen became the backbone of an army that would dominate the battlefield for centuries. The French once tried to master the use of the longbow but were unable to, so they went back to the crossbow, which was no match for the longbow in range, power, or rate of fire.

Under the Normans and Plantagenets, the English navy would grow in size and stature until it became a major sea power; then, during the reign of Elizabeth I, preeminent. The growth of England's sea power combined with her fine, professional army made England a world power.

England and the world would be much different today if Harold had won at Senlac.