In 1066, William the Conqueror launched an invasion of England. William had a claim to the English throne through his cousin, Edward the Confessor.
At the decisive Battle of Hastings, William defeated King Harold of Anglo-Saxons and effectively became the new ruler of England.
His conquest and rule also launched the feudal system in England which helped William cement his rule and secure his throne.
William the Conqueror invaded England in 1066. He had to fight several battles and put down many battles and struggles for many years before he could secure his hold over England.
Naturally, he believed that all the lands that he had invaded truly belonged to him.
So feudalism as a social system made perfect sense to him. As per feudalism, he proclaimed that he ultimately possessed all the land in England and could grant it to whoever he wished.
This granted him absolute powers to grant or confiscate lands. William used these powers to take land away from Anglo-Saxon nobles and give it to his loyal Norman-French barons.
The Norman lords and nobles who had fought alongside William in the conquest of England expected rewards. They felt entitled to lands they had conquered as they had toiled, fought, and sacrificed for it.
So there was a pressure on William the Conqueror to parcel out England to his lords and barons. Most of these lords already had land possessions back in Normandy and their new possessions in England were typically scattered here and there.
Even after William won the decisive Battle of Hastings, he had to face many rebellious barons and lords. He dealt with this problem by confiscating the properties of these lords and giving them to his loyal Normans.
In this way, the feudal system became a tool for William and the Normans to assert their control and authority over England. It also enabled William to ensure his rule over England despite lacking the infrastructure to directly impose this rule.
He left it up to his Norman nobility to impose this rule for him and pay fealty to him in turn. So effective was this rule by proxy that after 1072, William didn’t need to be in England to be its effective ruler.
In fact, he spent most of his time back in Normandy.
After the Norman Conquest of England in 1066, William and his men were very few compared to the overall population of England. William used a variety of tools to make sure that he could assert his authority despite the small numbers.
Militarily, he used mote-and-bailey castles which proved very effective. Socially, the feudal system helped him prop up a social ladder and establish a clear hierarchy.
By creating well-defined roles in this hierarchy, he was able to neutralize the strength of the vast numbers of native Anglo-Saxons of England.