1620, over a small point of precedence, when he was not satisfied till the king obliged De Cadenet to apologise. In April 1621 Arundel presided over the committee of the House of Lords appointed to consider the evidence against the lord chancellor, and recommended that Bacon should not be summoned to the bar of the house nor deprived of his peerage. On Bacon's fall he was, from 3 May to 10 July, joint-commissioner of the great seal. On 8 May 1621, when the House of Lords were discussing the case of Sir Henry Yelverton, who was in the Tower on the charge of attacking Buckingham in the House of Commons, Arundel dissuaded the lords from hearing Yelverton's own explanation of his words. Lord Spencer, as the representative of the popular party, hotly resented the suggestion that a man should be condemned unheard. A fierce altercation took place between Arundel and Spencer; finally, Arundel's advice was rejected, and his passionate language to Spencer was punished on 16 May by his committal to the Tower by order of the House of Lords. He was only released on the king's personal intercession with the lords, and on the engagement of the Prince of Wales that he would effect a reconciliation between the two peers. On 29 Aug. 1621 Arundel was appointed earl-marshal of England. At James's funeral he was one of Charles's supporters, and was afterwards made a commissioner to appoint the knights of the Bath and determine claims to perform the services required at the forthcoming coronation of the new king.
The earl soon declared himself an enemy of Buckingham, while his plain dress and haughty manner made him no favourite with the king. In the first year of Charles's reign, Arundel's eldest surviving son Henry Frederick, lord Maltravers, married Elizabeth, daughter of Esmé Stuart, for whom Charles had arranged another match. On this ground the king sent the young couple into confinement at Lambeth, and, to gratify his own and Buckingham's personal hostility to Arundel, ordered him and his wife to be confined first in the Tower and afterwards in their country house at Horseley, Sussex. But the lords demanded Arundel's release so peremptorily that Charles was obliged to yield, and the earl was set at liberty in June 1626. While he was suffering restraint Bacon was seized with what proved a fatal illness while journeying between London and Highgate, and took refuge at Arundel's house at Highgate (March 1626). Bacon died there 9 April 1626, and the last letter he wrote was to Arundel, thanking him for the hospitality afforded him during his enforced stay. Within a mouth of his release Arundel was again ordered into confinement in his own house, and remained under restraint till March 1628, when he was once more liberated at the instance of the lords. Throughout the debates on the Petition of Right of 1628 he tried to play the part of mediator, and probably drew up an amendment to the petition with the object of saving the royal prerogative, which was proposed by Lord Weston, and was finally carried in the House of Lords (Gardiner, vi. 279). Seeing, however, that, if the petition were to pass at all, further concession to the commons was necessary, Arundel assented to the withdrawal of the clause, and the prerogative was left undetermined. Weston in the same year effected a reconciliation between Arundel and the king, and he was restored to his place in the council.
In 1630 he revived the court of earl-marshal and constable. After the death of the king of Bohemia, Arundel was sent in December 1632 to the Hague to condole with the queen and bring her back to England; but she refused to come, alleging her duties to her family. In 1634 he was made chief justice in eyre of the forests north of the Trent; and in June accompanied Charles to his coronation in Scotland. In April 1636 Arundel was sent on an important political mission to the emperor at Vienna, to urge the restitution of the Palatinate to the king's nephew. For once he laid aside his plain dress, and was magnificently attired. On his journey he was received in state in Holland by the widowed queen of Bohemia, the Prince of Orange, and the States General. He travelled slowly on to Nuremberg. Thence he passed through the Upper Palatinate to Ratisbon, but, finding the diet not yet assembled, visited Ferdinand II at Linz and the queen of Hungary at Vienna. His demands as to the Palatinate were refused by the emperor, and he asked to be recalled. This Charles, who hoped to gain more favourable terms by temporising, refused. Passing through Moravia and Bohemia, Arundel returned to Ratisbon in the autumn (see Crowne, True Relation of … the Travels of Thomas Howard, Earl of Arundel…Embassador Extraordinary to…Ferdinand II, 1636, London, 1637, 12mo). Charles recalled him on 27 Sept. 1636, and on his return granted him 7,262l., the balance of 19,262l. allowed him for his expenses abroad. His mission completely altered his views of English foreign policy. He now regarded France instead of the house of Austria as the ally most valuable for England to secure in the matter of the Palatinate (cf. Gardiner, viii. 202). In 1638 Arundel was commissioned to repair