Testament,’ and other heretical books, is printed in ‘Four Supplications’ (Early English Text Soc. pp. x–xi). In 1527 he accompanied Wolsey on his embassy to France, and in the following years was one of the plenipotiaries who negotiated the famous treaty of Cambray (Letters and Papers, vol. iv. pt. iii. passim).
In the divorce question, which now became acute, Tunstall was said to have been one of those who would have been entirely on the emperor's side had it not been for Wolsey's influence, and Catherine chose him as one of her counsel; but he used his influence to dissuade her from appealing to Rome. On 21 Feb. 1529–30 he was papally provided to the bishopric of Durham in succession to Wolsey, who had held the see in commendam with the archbishopric of York. Temporary custody of the temporalities was granted him on 4 Feb., and plenary restitution was made on 25 March; he was succeeded in the bishopric of London by his friend and ally, John Stokesley [q. v.] Throughout the ensuing ecclesiastical revolution Tunstall's attitude was one of ‘invincible moderation.’ He retained till his death unshaken belief in catholic dogma, and he opposed with varying resolution all measures calculated to destroy it; but at the same time he seems to have believed in ‘passive obedience’ to the civil power, and even under Edward VI carried out ecclesiastical changes when sanctioned by parliament which he opposed before their enactment. Thus he protested against Henry VIII's assumption of the title of ‘supreme head’ even with the saving clause about the rights of the church (Wilkins, Concilia, vol. iii.; cf. Stowe MS. 141, f. 36), but he subsequently adopted it without reservation, remonstrated with Cardinal Pole on his attitude towards the royal supremacy, preached against the pope's authority in his diocese, and was selected to preach on Quinquagesima Sunday 1536 before four Carthusian monks condemned to death for refusing the oath of supremacy (Wriothesley, Chron. i. 34). He maintained it also in a sermon preached before the king on Palm Sunday 1539, which was published by Berthelet in the same year (London, 8vo), and reissued in 1633 (London, 4to). Tunstall's acquiescence in this and the other measures which completed the severance between the English church and Rome was of material service to Henry VIII, for, after the death of Warham and Fisher, Tunstall was beyond doubt the most widely respected of English bishops. Pole wrote in 1536 to Giberti that Tunstall was then considered the greatest of English scholars (Cal. State Papers, Venetian, 1534–54, No. 116). His influence was, however, occasionally feared by Henry, and previous to the parliament of 1536 which sanctioned the dissolution of the lesser monasteries, Tunstall was prevented from attending it, first by a letter from Henry excusing him from being present on account of his age, and secondly, when Tunstall was already near London, by a peremptory order from Cromwell to return (Gasquet, Henry VIII and the Monasteries, i. 151, 294).
In 1537 Tunstall was provided with a fresh field of activity by being appointed president of the newly created council of the north (State Papers, i. 554), and his voluminous correspondence in this capacity is now in the British Museum (Addit. MSS. 32647–32648). He was frequently appointed on commissions to treat with the Scots, and acted generally as experienced adviser to the successive lieutenant-generals appointed by Henry to defend the borders or invade Scotland. He continued, however, to take an active part in religious matters, and in 1537 he, as one of the commissioners appointed to draw up the ‘Institution of a Christian Man,’ endeavoured to make it as catholic in tone as possible. In 1538 he examined John Lambert (d. 1538) [q. v.] on the corporeal presence in the eucharist, and in the following year he submitted to Henry arguments in favour of auricular confession as of divine origin (the manuscript, with criticisms on the margin in Henry's own hand, is extant in Cottonian MS. Cleopatra E, v. 125). He attended the parliament of that year, which passed the act of six articles, asserting among other dogmas that auricular confession was ‘agreeable to the word of God,’ and in 1541 was published the ‘great bible’ in English, which was ‘overseene and perused’ by Tunstall and Nicholas Heath [q. v.] For the next few years Tunstall was chiefly occupied on the borders; in 1544 he was stationed at Newcastle during Hertford's invasion of Scotland. In November 1545 he was commissioned to negotiate peace with France (State Papers, x. 688), and in the following June was again sent to France to receive the ratification of the treaty of Ardres (ib.; Corr. Pol. de Odet de Selve, pp. 3–6). He returned in August, and attended the parliament that was sitting when Henry VIII died on 28 Jan. 1546–7.
During Edward VI's reign Tunstall's position became increasingly difficult, but his friendly relations with Somerset and Cranmer, combined with his own moderation, saved him at first from the consequences of his antipathy to their religious policy. He