Edward VI (12 October 1537 – 6 July 1553) became King of England and Ireland on 28 January 1547 and was crowned on 20 February at the age of nine. The son of Henry VIII and Jane Seymour, Edward was the third monarch of the Tudor dynasty and England's first ruler who was raised as a Protestant.

During Edward's reign, the realm was governed by a Regency Council, because he never reached maturity. The Council was led by his uncle Edward Seymour, 1st Duke of Somerset, (1547–1549), and then by John Dudley, 1st Earl of Warwick, (1550–1553), who later became Duke of Northumberland. Edward's reign was marked by economic problems, military withdrawal from Scotland and Boulogne-sur-Mer, and social unrest that, in 1549, erupted into riot and rebellion. It also saw the transformation of the Anglican Church into a recognisably Protestant body. Although Henry VIII had severed the link between the Church of England and Rome, he never permitted the renunciation of Catholic doctrine or ceremony. It was during Edward's reign that Protestantism was established for the first time in England with reforms that included the abolition of clerical celibacy and the Mass and the imposition of compulsory services in English. The architect of these reforms was Thomas Cranmer, Archbishop of Canterbury, whose Book of Common Prayer has proved lasting. Edward fell ill in January 1553, and when it was discovered to be terminal, he and his Council drew up a "Devise for the Succession", attempting to prevent the country being returned to Catholicism. Edward named his cousin Lady Jane Grey as his heir and excluded his half sisters, Mary and Elizabeth. However, this was disputed following Edward's death and Jane was only queen for nine days before Edward's half-sister, Mary, was proclaimed Queen. She proceeded to reverse many of Edward's Protestant reforms, but Elizabeth's religious settlement of 1559 would secure his Protestant legacy.

Prince Edward was born on 12 October 1537 at his mother's room inside of Hampton Court Palace, in Middlesex. He was the son of King Henry VIII by his third wife, Jane Seymour. Throughout the realm, the people greeted the birth of a male heir, "whom we hungered for so long", with joy and relief. Te Deums were sung in churches, bonfires lit, and "their was shott at the Tower that night above two thousand gonnes". Jane, appearing to recover quickly from the birth, sent out pre-signed letters announcing the birth of "a Prince, conceived in most lawful matrimony between my Lord the King's Majesty and us". Edward was christened on 15 October, with Princess Mary as godmother and Princess Elizabeth carrying the chrism, or baptismal cloth; and the Garter King of Arms proclaimed him as Duke of Cornwall and Earl of Chester. Jane Seymour, however, fell ill on 23 October from presumed postnatal complications, and died the following night. Henry VIII wrote to Francis I of France that "Divine Providence ... hath mingled my joy with bitterness of the death of her who brought me this happiness". Edward was a healthy baby who suckled strongly from the outset. His father was delighted with him; in May 1538, Henry was observed "dallying with him in his arms ... and so holding him in a window to the sight and great comfort of the people". That September, the Lord Chancellor, Thomas, Lord Audley, reported Edward's rapid growth and vigour; and other accounts describe him as a tall and merry child. The tradition that Edward VI was a sickly boy has been challenged by some historians. At the age of four, he fell ill with a life-threatening "quartan fever", but, despite occasional illnesses and poor eyesight, he enjoyed generally good health until the last six months of his life.

Edward was initially placed in the care of Margaret Bryan, "lady mistress" of the prince's household. She was succeeded by Blanche Herbert, Lady Troy. Until the age of six, Edward was brought up, as he put it later in his Chronicle, "among the women". The formal royal household established around Edward was, at first, under Sir William Sidney, and later Sir Richard Page, stepfather of Edward Seymour's wife, Anne Stanhope. Henry demanded exacting standards of security and cleanliness in his son's household, stressing that Edward was "this whole realm's most precious jewel". Visitors described the prince, who was lavishly provided with toys and comforts, including his own troupe of minstrels, as a contented child. From the age of six, Edward began his formal education under Richard Cox and John Cheke, concentrating, as he recalled himself, on "learning of tongues, of the scripture, of philosophy, and all liberal sciences"; He received tuition from Elizabeth's tutor, Roger Ascham and Jean Belmain, learning French, Spanish and Italian. In addition, he is known to have studied geometry and learned to play musical instruments, including the lute and the virginals. He collected globes and maps and, according to coinage historian C.E. Challis, developed a grasp of monetary affairs that indicates a high intelligence. Edward's religious education is assumed to have favoured the reforming agenda. His religious establishment was probably chosen by Archbishop Thomas Cranmer, a leading reformer. Both Cox and Cheke were "reformed" Catholics or Erasmians and later became Marian exiles. By 1549, Edward had written a treatise on the pope as Antichrist and was making informed notes on theological controversies. Many aspects of Edward's religion were essentially Catholic in his early years, including celebration of the mass and reverence for images and relics of the saints.

Both Edward's sisters were attentive to their brother and often visited him - on one occasion, Elizabeth gave him a shirt "of her own working". Edward "took special content" in Mary's company, though he disapproved of her taste for foreign dances; "I love you most", he wrote to her in 1546. In 1543, Henry invited his children to spend Christmas with him, signalling his reconciliation with his daughters, whom he had previously illegitimised and disinherited. The following spring, he restored them to their place in the succession with a Third Succession Act, which also provided for a regency council during Edward's minority. This unaccustomed family harmony may have owed much to the influence of Henry's new wife Catherine Parr, of whom Edward soon became fond. He called her his "most dear mother" and in September 1546, wrote to her: "I received so many benefits from you that my mind can hardly grasp them". Other children were brought to play with Edward, including the granddaughter of Edward's chamberlain, Sir William Sidney, who in adulthood recalled the prince as "a marvellous sweet child, of very mild and generous condition". Edward was educated with sons of nobles, "appointed to attend upon him" in what was a form of miniature court. Among these, Barnaby Fitzpatrick, son of an Irish peer, became a close and lasting friend. Edward was more devoted to his schoolwork than his classmates and seems to have outshone them, motivated to do his "duty" and compete with his sister Elizabeth's academic prowess. Edward's surroundings and possessions were regally splendid: his rooms were hung with costly Flemish tapestries, and his clothes, books, and cutlery were encrusted with precious jewels and gold. Like his father, Edward was fascinated by military arts, and many of his portraits show him wearing a gold dagger with a jewelled hilt, in imitation of Henry. Edward's Chronicle enthusiastically details English military campaigns against Scotland and France, and adventures such as John Dudley's near capture at Musselburgh in 1547.

On 1 July 1543, Henry VIII signed the Treaty of Greenwich with the Scots, sealing the peace with Edward's betrothal to the seven-month-old Mary, Queen of Scots. The Scots were in a weak bargaining position after their defeat at Solway Moss the previous November, and Henry, seeking to unite the two realms, stipulated that Mary be handed over to him to be brought up in England. When the Scots repudiated the treaty in December 1543 and renewed their alliance with France, Henry was enraged. In April 1544, he ordered Edward's uncle, Edward Seymour, Earl of Hertford, to invade Scotland and "put all to fire and sword, burn Edinburgh town, so razed and defaced when you have sacked and gotten what ye can of it, as there may remain forever a perpetual memory of the vengeance of God lightened upon [them] for their falsehood and disloyalty". Seymour responded with the most savage campaign ever launched by the English against the Scots. The war, which continued into Edward's reign, has become known as "The Rough Wooing".

Henry VIII died on 28 January 1547, when Edward was only nine. Those close to the throne, led by Edward Seymour and William Paget, agreed to delay the announcement of the king's death until arrangements had been made for a smooth succession. Seymour and Sir Anthony Browne, the Master of the Horse, rode to collect Edward from Hertford and brought him to Enfield, where Princess Elizabeth was living. He and Elizabeth were then told of the death of their father and heard a reading of the will. The Lord Chancellor, Thomas Wriothesley, announced Henry's death to parliament on 31 January, and general proclamations of Edward's succession were ordered. The new king was taken to the Tower of London, where he was welcomed with "great shot of ordnance in all places there about, as well out of the Tower as out of the ships". The following day, the nobles of the realm made their obeisance to Edward at the Tower, and Seymour was announced as Protector. Henry VIII was buried at Windsor on 16 February, in the same tomb as Jane Seymour, as he had wished.

Edward VI was crowned at Westminster Abbey four days later on Sunday 20 February, the first coronation in England for almost 40 years. The ceremonies were shortened, because of the "tedious length of the same which should weary and be hurtsome peradventure to the King's majesty, being yet of tender age", and also because the Reformation had rendered some of them inappropriate. On the eve of the coronation, Edward progressed on horseback from the Tower to the Palace of Westminster through thronging crowds and pageants, many based on the pageants for a previous boy king, Henry VI. He laughed at a Spanish tightrope walker who "tumbled and played many pretty toys" outside St Paul's Cathedral. At the coronation service, Cranmer affirmed the royal supremacy and called Edward a second Josiah, urging him to continue the reformation of the Church of England, "the tyranny of the Bishops of Rome banished from your subjects, and images removed". After the service, Edward presided at a banquet in Westminster Hall, where, he recalled in his Chronicle, he dined with his crown on his head.

Henry VIII's will named sixteen executors, who were to act as Edward's Council until he reached the age of 18. These executors were supplemented by twelve men "of counsail" who would assist the executors when called on. The final state of Henry VIII's will has been the subject of controversy. Some historians suggest that those close to the king manipulated either him or the will itself to ensure a shareout of power to their benefit, both material and religious. In this reading, the composition of the Privy Chamber shifted towards the end of 1546 in favour of the reforming faction. In addition, two leading conservative Privy Councillors were removed from the centre of power. Stephen Gardiner was refused access to Henry during his last months. Thomas Howard, 3rd Duke of Norfolk, found himself accused of treason; the day before the king's death his vast estates were seized, making them available for redistribution, and he spent the whole of Edward's reign in the Tower of London. Other historians have argued that Gardiner's exclusion was based on non-religious matters, that Norfolk was not noticeably conservative in religion, that conservatives remained on the Council, and that the radicalism of men such as Sir Anthony Denny, who controlled the dry stamp that replicated the king's signature, is debatable. Whatever the case, Henry's death was followed by a lavish hand-out of lands and honours to the new power group. The will contained an "unfulfilled gifts" clause, added at the last minute, which allowed Henry's executors to freely distribute lands and honours to themselves and the court, particularly to Edward Seymour, 1st Earl of Hertford, who became the Lord Protector of the Realm, Governor of the King's Person, and the Duke of Somerset. In fact, Henry VIII's will did not provide for the appointment of a Protector. It entrusted the government of the realm during his son's minority to a Regency Council that would rule collectively, by majority decision, with "like and equal charge". Nevertheless, a few days after Henry's death, on 4 February, the executors chose to invest almost regal power in Edward Seymour. Thirteen out of the sixteen (the others being absent) agreed to his appointment as Protector, which they justified as their joint decision "by virtue of the authority" of Henry's will. Seymour may have done a deal with some of the executors, who almost all received hand-outs. He is known to have done so with William Paget, private secretary to Henry VIII, and to have secured the support of Sir Anthony Browne of the Privy Chamber.

Seymour's appointment was in keeping with historical precedent, and his eligibility for the role was reinforced by his military successes in Scotland and France. In March 1547, he secured letters patent from King Edward granting him the almost monarchical right to appoint members to the Privy Council himself and to consult them only when he wished. In the words of historian G.R. Elton, "from that moment his autocratic system was complete". He proceeded to rule largely by proclamation, calling on the Privy Council to do little more than rubber-stamp his decisions. Somerset's takeover of power was smooth and efficient. The imperial ambassador, Van der Delft, reported that he "governs everything absolutely", with Paget operating as his secretary, though he predicted trouble from John Dudley, Viscount Lisle, who had recently been raised to Earl of Warwick in the share-out of honours. In fact, in the early weeks of his Protectorate, Somerset was challenged only by the Chancellor, Thomas Wriothesley, whom the Earldom of Southampton had evidently failed to buy off, and by his own brother. Wriothesley, a religious conservative, objected to Somerset's assumption of monarchical power over the Council. He then found himself abruptly dismissed from the chancellorship on charges of selling off some of his offices to delegates. His removal forestalled the forming of factions within the Council. Somerset faced less manageable opposition from his younger brother Thomas Seymour, who has been described as a "worm in the bud". As King Edward's uncle, Thomas Seymour demanded the governorship of the king's person and a greater share of power. Somerset tried to buy his brother off with a barony, an appointment to the Lord Admiralship, and a seat on the Privy Council — but Thomas was bent on scheming for power. He began smuggling pocket money to King Edward, telling him that Somerset held the purse strings too tight, making him a "beggarly king". He also urged him to throw off the Protector within two years and "bear rule as other kings do"; but Edward, schooled to defer to the Council, failed to co-operate. In April, using Edward's support to circumvent Somerset's opposition, Thomas Seymour secretly married Henry VIII's widow Catherine Parr, whose Protestant household included the 11-year-old Lady Jane Grey and the 13-year-old Princess Elizabeth.

In summer 1548, a pregnant Catherine Parr discovered Thomas Seymour embracing Princess Elizabeth. As a result, Elizabeth was removed from Catherine Parr's household and transferred to Sir Anthony Denny's. That September, Catherine Parr died in childbirth, and Thomas Seymour promptly resumed his attentions to Elizabeth by letter, planning to marry her. Elizabeth was receptive, but, like Edward, unready to agree to anything unless permitted by the Council. In January 1549, the Council had Thomas Seymour arrested on various charges, including embezzlement at the Bristol mint. King Edward, whom Seymour was accused of planning to marry to Lady Jane Grey, himself testified about the pocket money. Lack of clear evidence for treason ruled out a trial, so Seymour was condemned instead by an Act of Attainder and beheaded on 20 March 1549. The execution of his own brother was the latest of a series of disasters that had marked the Protector's rule. From this time, Somerset's own position was increasingly under threat.

Somerset's only undoubted skill was as a soldier, which he had proven on expeditions to Scotland and in the defence of Boulogne-sur-Mer in 1546. From the first, his main interest as Protector was the war against Scotland. After a crushing victory at the Battle of Pinkie Cleugh in September 1547, he set up a network of garrisons in Scotland, stretching as far north as Dundee. His initial successes, however, were followed by a loss of direction, as his aim of uniting the realms through conquest became increasingly unrealistic. The Scots allied with France, who sent reinforcements for the defence of Edinburgh in 1548, while Mary, Queen of Scots, was removed to France, where she was betrothed to the dauphin. The cost of maintaining the Protector's massive armies and his permanent garrisons in Scotland also placed an unsustainable burden on the royal finances. A French attack on Boulogne in August 1549 at last forced Somerset to begin a withdrawal from Scotland.

During 1548, England was subject to social unrest. After April 1549, a series of armed revolts broke out, fuelled by various religious and agrarian grievances. The two most serious rebellions, which required major military intervention to put down, were in Devon and Cornwall and in Norfolk. The first, sometimes called the Prayer Book Rebellion, arose mainly from the imposition of church services in English, and the second, led by a tradesman called Robert Kett, mainly from the encroachment of landlords on common grazing ground. A complex aspect of the social unrest was that the protesters believed they were acting legitimately against enclosing landlords with the Protector's support, convinced that the landlords were the lawbreakers. The same justification for outbreaks of unrest was voiced throughout the country, not only in Norfolk and the west. The origin of the popular view of Somerset as sympathetic to the rebel cause lies partly in his series of sometimes liberal, often contradictory, proclamations, and partly in the uncoordinated activities of the commissions he sent out in 1548 and 1549 to investigate grievances about loss of tillage, encroachment of large sheep flocks on common land, and similar issues. Somerset's commissions were led by an evangelical M.P. called John Hales, whose socially liberal rhetoric linked the issue of enclosure with Reformation theology and the notion of a godly commonwealth. Local groups often assumed that the findings of these commissions entitled them to act against offending landlords themselves. King Edward wrote in his Chronicle that the 1549 risings began "because certain commissions were sent down to pluck down enclosures". Whatever the popular view of Somerset, the disastrous events of 1549 were taken as evidence of a colossal failure of government, and the Council laid the responsibility at the Protector's door. In July 1549, Paget wrote to Somerset: "Every man of the council have misliked your proceedings ... would to God, that, at the first stir you had followed the matter hotly, and caused justice to be ministered in solemn fashion to the terror of others ...". By that autumn, plans were afoot to eject Somerset as Protector.

The sequence of events that led to Somerset's removal from power has often been called a coup d'état. By 1 October 1549, Somerset had been alerted that his rule faced a serious threat. He issued a proclamation calling for assistance, took possession of the king's person, and withdrew for safety to the fortified Windsor Castle, where Edward wrote, "Me thinks I am in prison". Meanwhile, a united Council published details of Somerset's government mismanagement. They made clear that the Protector's power came from them, not from Henry VIII's will. On 11 October, the Council had Somerset arrested and brought the king to Richmond. Edward summarised the charges against Somerset in his Chronicle: "ambition, vainglory, entering into rash wars in mine youth, negligent looking on Newhaven, enriching himself of my treasure, following his own opinion, and doing all by his own authority, etc." In February 1550, John Dudley, Earl of Warwick, emerged as the leader of the Council and, in effect, as Somerset's successor. Although Somerset was released from the Tower and restored to the Council, he was executed for felony in January 1552 after scheming to overthrow Dudley's regime. Edward noted his uncle's death in his Chronicle: "the duke of Somerset had his head cut off upon Tower Hill between eight and nine o'clock in the morning". Historians contrast the efficiency of Somerset's takeover of power, in which they detect the organising skills of allies such as Paget, the "master of practices", with the subsequent ineptitude of his rule. By autumn 1549, his costly wars had lost momentum, the crown faced financial ruin, and riots and rebellions had broken out around the country. Until recent decades, Somerset's reputation with historians was high, in view of his many proclamations that appeared to back the common people against a rapacious landowning class. More recently, however, he has often been portrayed as an arrogant and aloof ruler, lacking in political and administrative skills.

In contrast, Somerset's successor John Dudley, Earl of Warwick, made Duke of Northumberland in 1550, was once regarded by historians merely as a grasping schemer who cynically elevated and enriched himself at the expense of the crown. Since the 1970s, the administrative and economic achievements of his regime have been recognised, and he has been credited with restoring the authority of the royal Council and returning the government to an even keel after the disasters of Somerset's protectorate. The Earl of Warwick's rival for leadership of the new regime was Thomas Wriothesley, 1st Earl of Southampton, whose conservative supporters had allied with Dudley's followers to create a unanimous Council, which they, and observers such as the Holy Roman Emperor, Charles V's ambassador, expected to reverse Somerset's policy of religious reform. Southampton's faction intended to appoint the Catholic Princess Mary as regent for King Edward. Warwick, on the other hand pinned his hopes on the king's strong Protestantism and, claiming that Edward was old enough to rule in person, moved himself and his people closer to the king, taking control of the Privy Chamber. Paget, accepting a barony, joined Warwick when he realised that a conservative policy would not bring the Emperor onto the English side over Boulogne. Southampton prepared a case for executing Somerset, aiming to discredit Warwick through Somerset's statements that he had done all with Warwick's cooperation. As a counter-move, Warwick convinced parliament to free Somerset, which it did on 14 January 1550. Warwick then had Southampton and his followers purged from the Council after winning the support of Council members in return for titles, and was made Lord President of the Council and great master of the king's household. Although not called a Protector, he was now clearly the head of the government.

In accordance with his use of the king's personal authority as the source of his own, Warwick encouraged the king to come to Council meetings, which enabled him to cite the king's authority for his decisions. Although Edward was precocious and able to understand much government business, his contributions during Warwick's presidency probably amounted to no more than assent to decisions already taken. In Dale Hoak's view, "Edward VI's speeches and papers really present the somewhat pathetic figure of an articulate puppet far removed from the realities of government". His greatest influence was in matters of religion, where the Council followed the strongly Protestant policy that Edward favoured. The Duke of Northumberland's mode of operation was very different from Somerset's. Careful to make sure he always commanded a majority of councillors, he encouraged a working council and used it to legitimate his authority. Lacking Somerset's blood relationship with the king, he added members to the Council from his own faction in order to control it. He also added members of his family to the royal household. He saw that to achieve personal dominance, he needed total procedural control of the Council. In the words of historian John Guy, "Like Somerset, he became quasi-king; the difference was that he managed the bureaucracy on the pretence that Edward had assumed full sovereignty, whereas Somerset had asserted the right to near-sovereignty as Protector".

Warwick's war policies were more pragmatic than Somerset's, and they have earned him criticism for weakness. In 1550, he signed a peace treaty with France that agreed to withdrawal from Boulogne and recalled all English garrisons from Scotland. In 1551 Edward was betrothed to Elisabeth of Valois, King Henry II's daughter. In practice, he realised that England could no longer support the cost of wars. At home, he took measures to police local unrest. To forestall future rebellions, he kept permanent representatives of the crown in the localities, including lords lieutenant, who commanded military forces and reported back to central government. Warwick also tackled the disastrous state of the kingdom's finances, drawing on the talents of Thomas Smith, William Cecil, and William Paulet, and on the financial advice of men such as Walter Mildmay and Thomas Gresham. However, his regime did not take action until after it had succumbed to the temptations of a quick profit by further debasing the coinage. The economic disaster that resulted handed the initiative to the experts, and the debasement was reversed. By 1552, confidence in the coinage was restored, prices fell, and trade at last improved. Though a full economic recovery was not achieved until Elizabeth's reign, its origins lay in the Duke of Northumberland's policies. The regime also cracked down on widespread embezzlement of government finances, and carried out a thorough review of revenue collection practices, which has been called "one of the more remarkable achievements of Tudor administration".

In the matter of religion, the regime of Northumberland followed the same policy as that of Somerset, supporting an increasingly vigorous programme of reform. Although Edward VI's practical influence on government was limited, his intense Protestantism made a reforming administration obligatory; his succession was managed by the reforming faction, who continued in power throughout his reign. The man Edward trusted most, Thomas Cranmer, Archbishop of Canterbury, introduced a series of religious reforms that revolutionised the English church from one that — while rejecting papal supremacy, remained essentially Catholic — to one that was institutionally Protestant. The confiscation of church property that had begun under Henry VIII resumed under Edward — notably with the dissolution of the chantries — to the great monetary advantage of the crown and the new owners of the seized property. Church reform was therefore as much a political as a religious policy under Edward VI. By the end of his reign, the church had been financially ruined, with much of the property of the bishops transferred into lay hands. The religious convictions of both Somerset and Northumberland have proved elusive for historians, who are divided on the sincerity of their Protestantism. There is less doubt, however, about the religious devotion — some have called it bigotry — of King Edward, who was said to have read twelve chapters of scripture daily and enjoyed sermons, and was commemorated by John Foxe as a "godly imp". Edward was depicted during his life and afterwards as a new Josiah, the biblical king who destroyed the idols of Baal. He could be priggish in his anti-Catholicism and once asked Catherine Parr to persuade Princess Mary "to attend no longer to foreign dances and merriments which do not become a most Christian princess". Edward's biographer Jennifer Loach cautions, however, against accepting too readily the pious image of Edward handed down by the reformers, as in John Foxe's influential Acts and Monuments, where a woodcut depicts the young king listening to a sermon by Hugh Latimer. In the early part of his life, Edward conformed to the prevailing Catholic practices, including attendance at mass: but he became convinced, under the influence of Cranmer and the reformers among his tutors and courtiers, that "true" religion should be imposed in England.

The English Reformation advanced under pressure from two directions: from the traditionalists on the one hand and the zealots on the other, who led incidents of iconoclasm (image-smashing) and complained that reform did not go far enough. Reformed doctrines were made official, such as justification by faith alone and communion for laity as well as clergy in both kinds, of bread and wine. The Ordinal of 1550 replaced the divine ordination of priests with a government-run appointment system, authorising ministers to preach the gospel and administer the sacraments rather than, as before, "to offer sacrifice and celebrate mass both for the living and the dead". Cranmer set himself the task of writing a uniform liturgy in English, detailing all weekly and daily services and religious festivals, to be made compulsory in the first Act of Uniformity of 1549. The Book of Common Prayer of 1549, intended as a compromise, was attacked by traditionalists for dispensing with many cherished rituals of the liturgy, such as the elevation of the bread and wine, while some reformers complained about the retention of too many "popish" elements, including vestiges of sacrificial rites at communion. The prayer book was also opposed by many senior Catholic clerics, including Stephen Gardiner, Bishop of Winchester, and Edmund Bonner, Bishop of London, who were both imprisoned in the Tower and, along with others, deprived of their sees. After 1551, the Reformation advanced further, with the approval and encouragement of Edward, who began to exert more personal influence in his role as Supreme Head of the church. The new changes were also a response to criticism from such reformers as John Hooper, Bishop of Gloucester, and the Scot John Knox, who was employed as a minister in Newcastle under the Duke of Northumberland and whose preaching at court prompted the king to oppose kneeling at communion. Cranmer was also influenced by the views of the continental reformer Martin Bucer, who died in England in 1551, by Peter Martyr, who was teaching at Oxford, and by other foreign theologians. The progress of the Reformation was further speeded by the appointment of more reformers as bishops. In the winter of 1551–52, Cranmer rewrote the Book of Common Prayer in less ambiguous reformist terms, revised canon law, and prepared a doctrinal statement, the Forty-two Articles, to clarify the practice of the reformed religion, particularly in the divisive matter of the communion service. Cranmer's formulation of the reformed religion, finally divesting the communion service of any notion of the real presence of God in the bread and the wine, effectively abolished the mass. According to Elton, the publication of Cranmer's revised prayer book in 1552, supported by a second Act of Uniformity, "marked the arrival of the English Church at protestantism". The prayer book of 1552 remains the foundation of the Church of England's services. However, Cranmer was unable to implement all these reforms once it became clear in spring 1553 that King Edward, upon whom the whole Reformation in England depended, was dying.

In January 1553, Edward VI became ill, and by June, after several improvements and relapses, he was in a hopeless condition. The king's death and the succession of his Catholic sister Mary would jeopardise the English Reformation and Edward's Council and officers had many reasons to fear it. Edward opposed Mary's succession, not only on religious grounds but also on those of legitimacy and male inheritance, which also applied to Elizabeth. In February 1553, Mary made an official visit to Edward, welcomed by the Privy Council "as if she had been Queen of England", in the words of the imperial ambassador. Nevertheless, shortly before Edward's death, an attempt was made to subvert the succession. Henry VIII had set a precedent in that a king had nominated and excluded heirs of his own volition, independently of traditional rules of descent. With his draft document headed "My devise for the succession", King Edward also undertook to change the succession; he passed over the claims of the princesses Mary and Elizabeth and, at last, settled the Crown on his first cousin once removed, the sixteen-year-old Lady Jane Grey. On 21 May 1553, in what was a triple marriage ceremony "with a display truly regal", Lady Jane married Guildford Dudley, the fourth son of the Duke of Northumberland. Her sister Katherine wedded the son of the Earl of Pembroke, and a sister of Guildford was matched with a descendant of the Plantagenets, England's former royal family. In early June, Edward personally supervised the drafting of a clean version of his device by lawyers, to which he lent his signature "in six several places." Then, on 15 June, and under the watchful eye of the Duke of Northumberland, he summoned highranking judges and lawyers to his sickbed, commanding them on their allegiance "with sharp words and angry countenance" to prepare his device as letters patent and announced that he would have these passed in parliament. His next measure was to have leading councillors and lawyers sign a bond in his presence, in which they agreed faithfully to perform Edward's will after his death. Finally, on 21 June, the device was signed by over a hundred notables, including councillors, peers, archbishops, bishops, and sheriffs, many of whom later claimed that they had been bullied into doing so by Northumberland — three earls were helped along with their decisions by a substantial land grant.

When excusing his part in the business in a plea to Queen Mary a few months later, Chief Justice Edward Montagu recalled that when he and his colleagues had raised legal objections to the device, Northumberland came "into the Council Chamber ... being in a great rage and fury, trembling for anger, and amongst his rageous talk called the said Sir Edward, 'Traitor', and further said that he would fight in his shirt with any man in that quarrel". Later, as Edward personally demanded their obedience, Montagu overheard a bunch of lords standing behind him conclude "if they refused to do that, they were traitors". Thomas Cranmer, who was on bad terms with Northumberland and very reluctant to sign the documents, gave in only as Edward said he had expected him above all others to respect his will. It was now common knowledge that Edward was dying and that some scheme to debar Mary was underway. France, which found the prospect of the emperor's cousin on the English throne disagreeable, gave indications of support to Northumberland. The foreign diplomats, although certain that the overwhelming majority of the English people backed Mary, were nevertheless confident that Queen Jane would successfully be established: "The actual possession of power is a matter of great importance, especially among barbarians like the English", Simon Renard wrote to Charles V. Edward had often drafted political documents as exercises; in his last year, he increasingly applied this practice to the real business of government. One such document was the first draft of his "devise for the succession". Edward provided, in case of "lack of issue of my body", for the succession of male heirs only, that is, Jane Grey's mother's, Jane's or her sisters'. As his death approached and possibly persuaded by Northumberland, he altered the wording so that Jane and her sisters themselves should be able to succeed. Yet Edward conceded Jane's right only as an exception to male rule, demanded by reality, an example not to be followed if Jane or her sisters had only daughters. By the logic of the device, Frances Grey, Duchess of Suffolk, Jane's mother and Henry VIII's niece, should have been named as Edward's heir, but she, who had already been passed over in favour of her children in Henry's will, seems to have waived her claim after a visit to Edward. The letters patent of 21 June excluded both the king's half-sisters because of bastardy; as both had been declared bastards under Henry VIII, this reason could not only be advanced in Mary's but also in the Protestant Elizabeth's case. The provisions to alter the succession were in direct violation of Henry VIII's Third Succession Act of 1543 and the product of hurried and illogical thinking.

Whether the device was Edward's own idea or the result of manipulation by his advisors has been a matter of debate. For centuries, the attempt to alter the succession was mostly seen as a one-man-plot by the Duke of Northumberland. More recently, many historians have attributed the inception of the device and the insistence on its implementation to the king's initiative. Diarmaid MacCulloch has made out Edward's "teenage dreams of founding an evangelical realm of Christ", while David Starkey has stated that "Edward had a couple of co-operators, but the driving will was his". Dale Hoak, on the other hand, has argued: "the scheme to alter the succession originated in Northumberland's camp and not in King Edward's brain". Sir John Gates, a follower of Northumberland, has been suspected of presenting the drafts of the device to Edward, who then copied them out. Edward, who was convinced that his word was law, would have understood and endorsed either scenario: "barring Mary from the successsion was a cause in which the young King believed."

Edward became ill in January 1553 with a fever and cough that gradually worsened. The imperial ambassador, Scheyfve, reported that "he suffers a good deal when the fever is upon him, especially from a difficulty in drawing his breath, which is due to the compression of the organs on the right side ... I opine that this is a visitation and sign from God". Edward felt well enough in early April to take the air in the park at Westminster and to move to Greenwich, but by the end of the month he had weakened again. By 7 May he was "much amended" and the royal doctors had no doubt of his recovery. A few days later the king was watching the ships on the Thames, sitting at his window. However, he relapsed, and on 11 June Scheyfve, who had an informant in the king's household, reported that "the matter he ejects from his mouth is sometimes coloured a greenish yellow and black, sometimes pink, like the colour of blood". Now his doctors believed he was suffering from "a suppurating tumour" of the lung and admitted that Edward's life was beyond recovery. Soon, his legs became so swollen that he had to lie on his back, and he lost the strength to resist the disease. To his tutor John Cheke, he whispered "I am glad to die". Edward made his final appearance in public on 1 July, when he showed himself at his window in Greenwich Palace, horrifying those who saw him by his "thin and wasted" condition. During the next two days, large crowds arrived hoping to see the king again, but on the 3rd, they were told that the weather was too chilly for him to appear. Edward died at the age of 15 at Greenwich Palace on 6 July 1553. According to John Foxe's legendary account of his death, his last words were: "I am faint; Lord have mercy upon me, and take my spirit". He was buried in Henry VII Lady Chapel at Westminster Abbey on 8 August 1553, with reformed rites performed by Thomas Cranmer. The procession was led by "a grett company of chylderyn in ther surples" and watched by Londoners "wepyng and lamenting"; the funeral chariot, draped in cloth of gold, was topped by an effigy of Edward, with crown, sceptre, and garter. At the same time, Queen Mary attended a mass for his soul in the Tower, where Jane Grey was by then a prisoner.

The cause of Edward VI's death is not certain. As with many royal deaths in the 16th century, rumours of poisoning abounded, but no evidence has been found to support these. The Duke of Northumberland, whose unpopularity was underlined by the events that followed Edward's death, was widely believed to have ordered the imagined poisoning. Another theory held that Edward had been poisoned by Catholics seeking to bring Mary to the throne. The surgeon who opened Edward's chest after his death found that "the disease whereof his majesty died was the disease of the lungs". The Venetian ambassador reported that Edward had died of consumption — in other words, tuberculosis — a diagnosis accepted by many historians. Skidmore believes that Edward contracted the tuberculosis after a bout of measles and smallpox in 1552 that suppressed his natural immunity to the disease. Loach suggests instead that his symptoms were typical of acute bronchopneumonia, leading to a "suppurating pulmonary infection", septicaemia, and kidney failure.

Princess Mary, who had last seen Edward in February, was kept informed about the state of her brother's health by Northumberland and through her contacts with the imperial ambassadors; these also made her aware of some "mighty plot" to deprive her of the succession. Charles V advised her to accept the throne even if it were offered to her on condition she made no change in religion. Two days before Edward's death, she was summoned to court. Instead, she left Hunsdon House, near London, and sped to her estate at Kenninghall in Norfolk, fearing a trap. Northumberland sent ships to the Norfolk coast to prevent her escape or the arrival of reinforcements from the continent. He delayed the announcement of the king's death while he gathered his forces, and Jane Grey, who may not have been told of Edward's device until this moment, was taken to the Tower on 10 July. Later that day, she was proclaimed queen in the streets of London, to murmurings of discontent. Northumberland now pressed Jane to make his son Guildford Dudley king, which, according to her own account, she refused to do. The Privy Council received a message from Mary asserting her "right and title" to the throne and commanding that the Council proclaim her queen, as she had already proclaimed herself. The Council replied that Jane was queen by Edward's authority and that Mary, by contrast, was illegitimate and supported only by "a few lewd, base people".

Northumberland soon realised that he had miscalculated drastically, not least in failing to secure Mary's person before Edward's death. Although many of those who rallied to Mary were conservatives hoping for the defeat of Protestantism, her supporters also included many legitimists, for whom her lawful claim to the throne overrode religious considerations. Northumberland was obliged to relinquish control of a nervous Council in London and launch an unplanned pursuit of Mary into East Anglia, from where news was arriving of her growing support, which included a number of nobles and gentlemen and "innumerable companies of the common people". In this precarious situation, Northumberland sent a secret mission to France to secure a pledge of French support. Next, the duke marched out of London with three thousand men, reaching Cambridge on 14 July; meanwhile, Mary rallied her forces at Framlingham Castle in Suffolk, gathering an army of nearly twenty thousand by 19 July. It now dawned on the Privy Council that it had made a terrible mistake. When news reached the councillors in the Tower that even the Norfolk fleet had declared for Mary, they abandoned Northumberland and offered a reward for his arrest. On 19 July, the Council completed its turnabout by publicly proclaiming Mary as queen; and Jane's nine-day reign came to an end. The proclamation triggered wild rejoicing throughout London. Stranded in Cambridge, Northumberland had no alternative, as a member of the Council, but to proclaim Mary himself. William Paget and the Earl of Arundel rode to Framlingham to beg Mary's pardon, and Arundel arrested Northumberland on 24 July. Northumberland was beheaded on 22 August, shortly after renouncing Protestantism. His recantation dismayed his daughter-in-law, Jane, who followed him to the scaffold on 12 February 1554, after her father's involvement in Wyatt's rebellion.