William not only recovered the tithes from the Church of England, but also attacked the Archbishop of Canterbury, not only deposing Father Stepander as Archbishop of Canterbury, but also sending Father Stigander to the royal court for corruption and collusion with the rebellious aristocracy.

During his tenure as Archbishop of Canterbury, Father Stigander amassed an enviable fortune that even William coveted, and this time William went against Father Stigander for his vast wealth.

The royal court was William's weapon against the Church, and soon Father Stigander was convicted and stripped of the Archbishop of Canterbury, who subsequently returned all his property to the Crown.

Because Father Stigander's family was also rich because of his participation in Stigand's crazy accumulation of wealth, William also made up the crime and stripped all of Father Stigander's family of their property and sent them to prison.

The Archbishop of York, the head of the Church of England, who presided over William's coronation, was highly respected among the nobility and clergy of England.

In order to oppose William's tyrannical rule, the Archbishop of York resolutely resisted the king's demand for the recovery of tithes, opposed William's decision to remove the Archbishop of Canterbury, and demanded the return of all ecclesiastical assets.

To this end, he sent his most trusted priest Fernes, Father Boulgild, to Rome to appeal to the Pope and accuse William of his crimes.

At the same time, in response, the Archbishop of York elected the Anglo-Saxon priest Edric as the Archbishop of Canterbury, despite the new Archbishop of Canterbury appointed by the royal court.

William was furious, and the Archbishop of York took the lead in repeatedly opposing himself, which was a serious provocation to his authority.

In retaliation, in the spring of 1048, William ordered the confiscation of part of the income of priests and clergy vassals, which was again resisted by the bishops.

Soon after, the king asked the clergy to pay 1/13 of their movable property and income to the royal family, but the Archbishop of York resisted, but he was forced by the king to leave England and go into exile.

As the conflict escalated, William confiscated the property and income of the bishopric and the monastery that had become vacant due to the death and flight of the incumbent to the royal family, despite the opposition of the church.

According to incomplete estimates, the income from the church, which appears only in the royal books, was £400 when William was crowned King of England in 1045, but in the last quarter of 1047 after William's reform of the Church of England, the income from the church reached £5,700, and it is expected that this income will swell to £24,000 in the whole of 1048.

In August 1048, the papal intervention came as expected, and the new Pope Kedamassus II sent an envoy to reprimand William's brutal march, appointing Edric as the Archbishop of Canterbury instead of recognizing the Archbishop of Canterbury Herman, who had been appointed by William, and appointing the fugitive Archbishop of York as Cardinal.

In fact, the conflict between church and secular power at this time was, to a large extent, a confrontation between the English feudal crown and the Holy See for the right to rule the English Church, and the English church aristocracy basically did not confront the king head-on when the conflict intensified.

On August 9, 1048, Count Nordgaard and Bishop Bruno, cousin of the Holy Roman Emperor Henry III, ascended to the throne of St. Peter with the help of Henry III and succeeded him as Pope, called Leo IX.

Like his two predecessors, Leo IX reigned for five years (1049-1054) and was a strong supporter of the Cluny movement, and it was because of his enthusiasm for reform that he was appointed pope by the emperor.

He ordered the reorganization of the Holy See, with the clergy all held by Cluny monks, demanded strict celibacy at all levels of clergy, prevented the transfer of religious property to the laity, and declared that all religious property belonged to the Pope and was liable to pay taxes to the Holy See.

As a zealous Cluny monk, William's forcible repossession of ecclesiastical property, abolition of parishes, tithes, and appointment and dismissal of priests were naturally hostile to Leo IX.

In 1048, after Pope Leo IX issued the "Prohibition of Christianity" prohibiting the holding of relevant religious services in England, some English bishops fled to Scotland and mainland Europe, which greatly affected the normal religious life of the people.

However, the religious activities in Britain did not completely cease, and William also "elected" new bishops in four dioceses, including Chester, Exeter, Lincoln, and Lickfield.

At the same time, as William's close confidants, the Norman bishops such as Silvestre, Bishop of Suthwark, Frante, Bishop of Abingdon, and Whitemont, Bishop of St. Paul, were all important courtiers of King William, and they frequently participated in state affairs.

Later, William frequently deposed the Anglo-Saxon bishops in the counties, and at the same time appointed Norman priests as bishops and priests in charge of the county parish monasteries.

With the deepening of William's Reformation, most of the dioceses, bishops, parishes and monasteries in the Kingdom of England have been controlled by Norman bishops and priests appointed by William, and the tithes originally collected by the Church of England have also been continuously remitted into William's royal treasury.

In October 1048, the Pope, seeing William's repeated teachings, announced that William would be excommunicated, demanding that William pay tribute to the Pope, return the looted ecclesiastical property, let the Archbishop of York return to England, and compensate the Church of England for the losses suffered during the conflict.

William's religious law was forbidden for any believer, so many bishops loyal to him had to leave England, but many bishops and clergy remained loyal to William despite the Pope's orders.

Most of them were newly appointed Norman bishops and priests by William, and almost all of them were Anglo-Saxons.

William was the king of the Normans, and he and all the Normans were a community of interests, and the close relationship between them was not a simple law issued by the pope in Rome, and it was possible to simply excommunicate William.

On the other hand, fed up with the restrictions and exploitation of the church, William was determined to fight the Holy See to the end this time.

In November 1048, the Council of England passed the Act of Supremacy, declaring the King the sole and supreme head of the Church of England and severing all contact with the Pope.

The enactment of the Act of Supremacy meant that William was not only the supreme ruler of the world, but also the supreme ruler of religion, and all churches in England were no longer under the command of the Pope.

After the break with the Holy See, the Church of England was called "Anglicanism", also known as "Anglicanism", and had the status of a state religion.

William's fundamental purpose of the Reformation was to suppress the clergy and strengthen the power of the crown, not only did he not change the doctrine much, but even he himself did not renounce the Catholic faith, and the reformed Anglicanism retained the Catholic tradition such as the bishopric system.

Subsequently, William successively formulated the "Ten Canons", simplified the Catholic rites, issued the "Seventeen Directives", the state religion and the state institutionalized the English Parliament, abolished the monastic system, confiscated monastic lands, and killed many opponents.

From then on, the Church of England broke away from the Pope, and the Church of England was founded.