In 1547, Dudley was created Earl of Warwick and, with the Duke of Somerset, England's Lord Protector, distinguished himself in the renewed Scottish war at the Battle of Pinkie Cleugh.

Having averted a conservative reaction in religion and a plot to destroy him alongside Somerset, Dudley emerged in early 1550 as de facto regent for the 12-year-old Edward VI.

The 15-year-old King fell ill in early 1553 and excluded his half-sisters, Mary and Elizabeth, whom he regarded as illegitimate, from the succession, designating non-existent, hypothetical male heirs.

[2] His father was attainted and executed for high treason in 1510, having been arrested immediately after Henry VIII's accession because the new king needed scapegoats for his predecessor's unpopular financial policies.

Dudley took part in the christenings of the King's children, Elizabeth and Edward[15] and, in connection with the announcement of the Prince's birth to the Emperor, travelled to Spain via France in October 1537.

[22] In the aftermath of the Battle of Solway Moss in 1542, he served as Warden of the Scottish Marches, and in the 1544 campaign the English force under Edward Seymour, Earl of Hertford, was supported by a fleet which Dudley commanded.

[25] As Lord Admiral, Dudley was responsible for creating the Council for Marine Causes, which for the first time co-ordinated the various tasks of maintaining the navy functioning and thus made English naval administration the most efficient in Europe.

When he suspected the Admiral of France, Claude d'Annebault, of manoeuvres which might have led to a renewal of hostilities, he suddenly put to sea in a show of English strength, before returning to the negotiating table.

[31] Dudley and the Queen's brother, William Parr, 1st Earl of Essex, tried to convince Anne Askew to conform to the Catholic doctrines of the Henrician Church, yet she replied "it was great shame for them to counsel contrary to their knowledge".

[32] In the last weeks of the reign Seymour and Dudley played their parts in Henry's strike against the conservative House of Howard, thus clearing the path for a Protestant minority rule.

This was rejected and the next night Dudley stormed the rebel-held city with a small mercenary contingent and drove the rebels out after fierce street fighting; 49 prisoners he had immediately hanged.

Military force near King Edward's presence was unthinkable and, apparently, Dudley and Archbishop Thomas Cranmer brokered an unofficial deal with Somerset, who surrendered.

[62] Yet Somerset soon attracted political sympathizers and hoped to re-establish his power by removing Dudley from the scene,[63] "contemplating", as he later admitted, the Lord President's arrest and execution.

[73] Instead of taking the title of Lord Protector, John Dudley set out to rule as primus inter pares, the working atmosphere being more conciliar and less autocratic than under Somerset.

[78] William Cecil was still in the Duke of Somerset's service when he gradually shifted his loyalty to John Dudley, who made him Secretary of State and thought him "a most faithful servant and by that term most witty [wise] councillor ... as was scarce like in this realm".

[92] He returned to the ancient practice of granting licences to retain liveried followers and installed lord-lieutenants that represented the central government and were to keep ready small bands of cavalry.

[109] The English government could not swallow a war threat from an ambassador who had stepped out of his commission, but at the same time would not risk all-important commercial ties with the Habsburg Netherlands, so an embassy was sent to Brussels and some of Mary's household officers were arrested.

[110] On his next visit to the council, Scheyfye was informed by the Earl of Warwick that the King of England had as much authority at 14 as he had at 40—Dudley was alluding to Mary's refusal to accept Edward's demands on grounds of his young age.

[114] The 1552 revised edition of the Book of Common Prayer rejected the doctrine of transubstantiation, and the Forty-two Articles, issued in June 1553, proclaimed justification by faith and denied the existence of purgatory.

On 21 May 1553 Guildford Dudley, Northumberland's second youngest son, married Lady Jane Grey, the fervently Protestant daughter of the Duke of Suffolk and, through her mother Frances Brandon, a grandniece of Henry VIII.

[158][note 3] Around the end of May or early June Edward's condition worsened dramatically and he corrected his draft such that Lady Jane Grey herself, not just her putative sons, could inherit the Crown.

[169] Antoine de Noailles wrote of Guildford Dudley as "the new King", while the Emperor instructed his envoys to arrange themselves with the Duke and to discourage Mary from undertaking anything dangerous.

[174] Faced with Edward's express royal will and perseverance, John Dudley submitted to his master's wishes—either seeing his chance to retain his power beyond the boy's lifetime or out of loyalty.

[182] Supported by gentry and nobility in East Anglia and the Thames Valley, Mary's military camp was gathering strength daily and, through luck, came into possession of powerful artillery from the royal navy.

"[198] A great propaganda coup for the new government, Dudley's words were officially distributed—especially in the territories of the Emperor Charles V.[199] In the evening the Duke learnt "that I must prepare myself against tomorrow to receive my deadly stroke", as he wrote in a desperate plea to the Earl of Arundel: "O my good lord remember how sweet life is, and how bitter ye contrary.

[211] However, he saw the King on the verge of assuming full authority at the beginning of 1553 (with Dudley contemplating retirement) and ascribed the succession alteration to Edward's resolution, Northumberland playing the part of the loyal and tragic enforcer instead of the original instigator.

[note 6] Others, while remarking upon the plan's sloppy implementation,[213] have seen Northumberland as behind the scheme, yet in concord with Edward's convictions; the Duke acting out of despair for his own survival,[50] or to rescue political and religious reform and save England from Habsburg domination.

[214] Since the 1970s, critical reassessments of the Duke of Somerset's policies and government style led to acknowledgment that Northumberland revitalised and reformed the Privy Council as a central part of the administration,[215] and that he "took the necessary but unpopular steps to hold the minority regime together".

[222] Further explanations—both contemporary and modern—have been that Northumberland sought to rescue his family from the axe,[223] that, in the face of catastrophe, he found a spiritual home in the church of his childhood,[224] or that he saw the hand of God in Mary's success.

[237] Frequent phases of illness, partly due to a stomach ailment, occasioned long absences from court but did not reduce his high output of paperwork, and may have had an element of hypochondria in them.