A useful courtier
A member of the royal secretariat, Wriothesley and William Brereton were charged with helping secure an annulment for the King against Katherine of Aragon from Pope Clement VII to allow Anne Boleyn to assume her royal position; they were sent out to get members of the nobility to sign written statements indicating assent to the annulment.
Wriothesley was at Windsor with the Court when the series of protests known as the Pilgrimage of Grace broke out in reaction to the religious changes brought in by the crown and its advisors. The Clerk of the Signet admired the King but probably learnt lessons of cruelty from the treatment of Robert Aske in 1536. "It was upon such men that the King relied at times of crisis". Wriothesley's services were richly rewarded at the Dissolution of the Monasteries. He was granted extensive lands between Southampton and Winchester, once belonging to the abbeys of Beaulieu and Titchfield. Even with the retrospection of later life he was able to 'forget' the excesses of the 1530s, Wriothesley was still able to exaggerate his fidelity to his "benign and pleasant' King, whom he knew only in the febrile atmosphere of the Court.
Until May 1539, he was Henry VIII's ambassador in Brussels. In late 1539, Anne of Cleves was due to come from the German duchy to England, and Wriothesley was to lead the naval escort. On 27 December the Princess arrived at Deal in Kent, from whence she was shown to Dover Castle. On New Years Day the party reached Rochester Castle. Wriothesley continued to support Norfolk's Catholic party, but only when it suited him at court, as parties emerged between the reformists and conservatives. In the absence of a predominant figure the Council became more conciliar towards the end of the reign. Having been sent on diplomatic errands abroad, in 1540 Sir Thomas Wriothesley was made one of the King's principal secretaries (a position he held jointly with Sir Ralph Sadler), acting as Secretary to the Privy Council. Dividing the duties, Sadler's responsibility was as personal secretary to the King, whereas Wriothesley's were purely political. Wriothesley was rewarded with the dissolved abbey of Titchfield for good service to the King. He rapidly converted it into a country house, which became the family's ancestral seat. Wriothesley's noble parentage and strong personality enabled him to dominate the commoner Sadler. Knighted in 1540, Wriothesley made friends with Sir Anthony Browne of the refounded Gentleman Pensioners, who acted as an armed bodyguard of the King pursuant to the Greenwich Ordinances.
The expansion of the Pensioners from 50 to 350 members signalled the resurgence of the conservative noble faction at court during the 1540s. Wriothesley, having earned his place at court as a faithful attendant to Thomas Cromwell, betrayed Cromwell in 1540, telling the King that Cromwell was indiscreet about Henry's inability to consummate his marriage to Anne of Cleves. This news, coupled with the Cleves alliance threatening war with Emperor Charles V, proved Cromwell's undoing. Wriothesley happily lied to the council and betrayed his master, in order to take his place beside the King.
Queen Katherine Howard's conviction and execution for adultery signalled that the political pendulum was swinging away from Norfolk once more. On 13 November 1541, Secretary Wriothesley was sent to announce the bad news to members of the Queen's Household at Hampton Court; all her chamber were dismissed and sent home. In 1542 it was said that Wriothesley governed almost everything in England. He sought to bring about an alliance between England and Spain in 1543. Wriothesley was one of the Council led by Catholic Bishop Stephen Gardiner, who ordered the imprisonment of Henry Howard, Earl of Surrey for being drunk and disorderly. He supported Gardiner's crackdown against Lutheran opinions, threatening the lives of reformers Miles Coverdale and Hugh Latimer, presaging the reign of Mary I. All Protestants were rooted out of the royal household, with those of the new extreme Puritan sect Calvinism being treated with especial prejudice. The Council even intimidated Archbishop Thomas Cranmer, who was protected by the King himself. Sir Ralph Sadler was ousted as the principal secretary to the King, to be replaced by the more judicious and discreet William Paget. But the rise of the conservatives meant Wriothesley had eventually to go, in January 1544, in favour of the openly Catholic Sir William Petre. Fortunately for Cranmer and others, the King was not prepared to turn the clock back to the 1530s, and Katherine Parr, with her experience in two previous marriages, impressed Wriothesley by offering Henry stability in his old age. Furthermore, as governess to Henry VIII's daughter Elizabeth, bringing the children to court at Christmas 1543, Parr showed off what Wriothesley had accurately predicted to be Elizabeth's promise as a future leader.