He was appointed in 1651 lieutenant-general in the French army, and commander of the forces in Flanders. These new honours, however, were soon lost. During Mazarin's enforced absence from the court Digby aspired to become his successor; and the cardinal, who had from the first penetrated his character and regarded him as a mere adventurer, on his restoration to power sent Digby away on an expedition in Italy; and on his return informed him that he was included in the list of those expelled from France, in accordance with the new treaty with Cromwell. In August 1656 he joined Charles II. at Bruges, and desirous of avenging himself upon the cardinal offered his services to Don John of Austria in the Netherlands, being instrumental in effecting the surrender of the garrison of St Ghislain to Spain in 1657. On the 1st of January 1657 he was appointed by Charles II. secretary of state, but shortly afterwards, having become a Roman Catholic - probably with the view of adapting himself better to his new Spanish friends - he was compelled to resign office.
Charles, however, on account of his "jollity" and Spanish experience took him with him to Spain in 1659, though his presence was especially deprecated by the Spanish; but he succeeded in ingratiating himself, and was welcomed by the king of Spain subsequently at Madrid.
By the death of his father Digby had succeeded in January 1659 to the peerage as 2nd earl of Bristol, and had been made K.G. the same month. He returned to England at the restoration, when he found himself excluded from office on account of his religion, and relegated to only secondary importance. His desire to make a brilliant figure induced a restless and ambitious activity in parliament. He adopted an attitude of violent hostility to Clarendon. In foreign affairs he inclined strongly to the side of Spain, and opposed the king's marriage with Catherine of Portugal. He persuaded Charles to despatch him to Italy to view the Medici princesses, but the royal marriage and treaty with Portugal were settled in his absence. In June 1663 he made an attempt to upset Clarendon's management of the House of Commons, but his intrigue was exposed to the parliament by Charles, and Bristol was obliged to attend the House to exonerate himself, when he confessed that he had "taken the liberty of enlarging," and his "comedian-like speech" excited general amusement.
Exasperated by these failures, in a violent scene with the king early in July, he broke out into fierce and disrespectful reproaches, ending with a threat that unless Charles granted his requests within twenty-four hours "he would do somewhat that should awaken him out of his slumbers, and make him look better to his own business." Accordingly on the 10th he impeached Clarendon in the Lords of high treason, and on the charge being dismissed renewed his accusation, and was expelled from the court, only avoiding the warrant issued for his apprehension by a concealment of two years. In January 1664 he caused a new sensation by his appearance at his house at Wimbledon, where he publicly renounced before witnesses his Roman Catholicism, and declared himself a Protestant, his motive being probably to secure immunity from the charge of recusancy preferred against him. When, however, the fall of Clarendon was desired, Bristol was again welcomed at court. He took his seat in the Lords on the 29th of July 1667. "The king," wrote Pepys in November, "who not long ago did say of Bristoll that he was a man able in three years to get himself a fortune in any kingdom in the world and lose all again in three months, do now hug him and commend his parts everywhere above all the world." He pressed eagerly for Clarendon's commital, and on the refusal of the Lords accused them of mutiny and rebellion, and entered his dissent with "great fury." In March 1668 he attended prayers in the Lords. On the 15th of March 1673 though still ostensibly a Roman Catholic, he spoke in favour of the Test Act, describing himself as "a Catholic of the church of Rome, not a Catholic of the court of Rome," and asserting the unfitness of Romanists for public office.
His adventurous and erratic career closed by death on the 20th of March 1677.
Bristol was one of the most striking and conspicuous figures of his time, a man of brilliant abilities, a great orator, one who distinguished himself without effort in any sphere of activity he chose to enter, but whose natural gifts were marred by a restless ambition and instability of character fatal to real greatness. Clarendon describes him as "the only man I ever knew of such incomparable parts that was none the wiser for any experience or misfortune that befell him," and records his extraordinary facility in making friends and making enemies. Horace Walpole characterized him in a series of his smartest antitheses as "a singular person whose life was one contradiction." "He wrote against popery and embraced it; he was a zealous opposer of the court and a sacrifice for it; was conscientiously converted in the midst of his prosecution of Lord Strafford and was most unconscientiously a persecutor of Lord Clarendon. With great parts, he always hurt himself and his friends; with romantic bravery, he was always an unsuccessful commander.
He spoke for the Test Act, though a Roman Catholic; and addicted himself to astrology on the birthday of true philosophy." Besides his youthful correspondence with Sir K. Digby on the subject of religion already mentioned, he was the author of an Apologie (1643, Thomason Tracts, E. 34 (32)), justifying his support of the king's cause; of Elvira ... a comedy (1667), printed in R. Dodsley's Select Collect. of Old English Plays (Hazlitt, 1876), vol. xv., and of Worse and Worse, an adaptation from the Spanish, acted but not printed. Other writings are also ascribed to him, including the authorship with Sir Samuel Tuke of The Adventures of Five Hours (1663). His eloquent and pointed speeches, many of which were printed, are included in the article in the Biog. Brit. and among the Thomason Tracts; see also the general catalogue in the British Museum. The catalogue of his library was published in 1680. He married Lady Anne Russell, daughter of Francis, 4th earl of Bedford, by whom, besides two daughters, he had two sons, Francis, who predeceased him unmarried, and John, who succeeded him as 3rd earl of Bristol, at whose death without issue the peerage became extinct.
See the article in Dict. Nat. Biog.; Wood's Ath. Oxon. (Bliss), iii. 1100-1105; Biographia Brit. (Kippis), v. 210-238; H. Walpole's Royal and Noble Authors (Park, 1806), iii. 191; Roscius Anglicanus, by J. Downes, pp. 31, 36 (1789); Cunningham's Lives of Eminent Englishmen (1837), iii. 29; Somers Tracts (1750), iii. (1809), iv.; Harleian Miscellany (1808), v., vi.; Life by T. H. Lister (1838); State Papers.
(P. C. Y.)
 I.e. in the Digby line; for the Herveys see above.
 Clarendon State Papers, ii. 201.
 Mémoires du Cardinal de Retz (1859), app. iii. 437, 442.
 Pepys's Diary, iv. 51.
 Ib. vii. 199.
 Ib. 207; Protests of the Lords, by J.E.T. Rogers, i. 36.