Digby’s cousin, Sir Kenelm Digby, traced their family’s ancestry back to Saxon times in a bogus pedigree, a piece of antiquarian one-upmanship which discounted their verifiable thirteenth-century origins. Robert Digby was returned as knight for Leicestershire in 1373, but the family’s political interest thereafter shifted to Rutland. His younger grandson, lieutenant of the Tower under Henry VII, was granted the manor of Coleshill, Warwickshire in 1495, an estate subsequently enlarged by marriage and purchase. Digby’s father was of sufficient standing to be returned as knight for Warwickshire in 1581 and 1584.
As a younger son, Digby received a life annuity of only £40, half of which initially went towards the costs of his education at Oxford and the Inner Temple. Having apparently travelled abroad, he was presented at Court in 1604, when his mother recommended him to Viscount Cranborne (Robert Cecil†). As the latter had relatively little influence in the privy chamber, Digby probably secured his post as carver through the efforts of the treasurer of the Household, William, 1st Baron Knollys†, whose niece Lady Offaly was married to Digby’s brother Sir Robert. It was undoubtedly this position which brought him to the king’s attention, as James liked a ‘trial of wits’ at mealtimes; George Villiers was to make his initial mark at Court as a cupbearer.
While Salisbury may have had little influence over Digby’s Court career, he was undoubtedly responsible for his return to Parliament. In the autumn of 1609 the earl approached the corporation at Hedon, where one seat had lain vacant since December 1607. The townsmen agreed to send up a blank indenture on the understanding that the Member chosen should ‘in every respect defray his own charges and no ways be burdensome to us’, a condition Digby was well placed to fulfil. For some unknown reason Digby’s return was rejected by the Commons on 26 Mar. 1610, but the defect was remedied by a new return on 7 April. Digby first appeared in the records of the session on 17 Apr., when he was appointed to a committee to scrutinize a bill against ‘untimely hawking’. On the following day he was named to the committee for the bill to naturalize Salisbury’s secretary Levinus Munck†. His only other recorded contribution to the Parliament was as one of a deputation which presented the Commons’ grievances to the king on 7 July.
Digby was presumably not expected to play a significant role in Parliament in 1610, but his low profile may have owed something to his involvement in a dispute on his wife’s behalf. Lady Digby was being sued by Isabell Brounker, the mistress of her first husband Sir John Dyve, for payment of a debt of £3,000 under a bond plausibly claimed to be a forgery. However, Brounker may have had a genuine grievance, as she believed that her adversary, having secured administration of Dyve’s goods in 1607, had suppressed a will in which Dyve had made generous provision for his bastard son. Digby could not afford any diminution of his wife’s jointure income, estimated at £1,200 a year, and consequently a Star Chamber suit was brought against Brounker for forgery in January 1610. She had powerful allies, however, as her husband was a servant of Lord Bruce, the master of the Rolls, and the quarrel might have continued for years but for the fact that Digby’s servants managed to eject Brounker from her house, held under a lease from Dyve, in July 1610; Brounker probably dropped her suit in return for readmission to her home.
Digby was appointed ambassador to Spain two weeks before Parliament reconvened in the autumn of 1610. As he did not leave for Madrid until April 1611, he probably attended the session, although he left no trace upon the poorly recorded debates. His selection for such an important post seems surprising, as his only prior experience of diplomacy had been to deputize for the master of ceremonies, Sir Lewis Lewknor*, at a meeting with the French ambassador in January 1610. His apparent sympathy for his Catholic relatives may have recommended him for the post, but his cause was probably promoted by the pro-Spanish Howard faction, to whom he was linked through Knollys. While abroad he corresponded with both the head of the Howard family, Henry, earl of Northampton, and the king’s favourite, Robert Carr.
Digby apparently made a considerable impact at the Spanish Court: the Venetian ambassador described him as ‘a person of great prudence and ability who will live sumptuously, for in addition to the thousand crowns [£250] a month of salary which his king assigns him, he is very rich and can supply all that is required’.
Digby returned to England in the spring of 1614, arriving soon after the opening of the Addled Parliament with intelligence about the identities of the Spanish pensioners at the Jacobean Court. His diplomatic post prevented him from seeking election to the Commons, and he returned to Spain in the autumn.
Digby was sent back to Spain in 1617 with further terms for a Spanish Match, but Philip III was not prepared to strike a deal without substantial concessions on toleration, which James was not then prepared to concede; Digby thus returned to London empty-handed in May 1618. He received a barony as a reward for his efforts, and was subsequently elevated to the earldom of Bristol. However, he was sent back to Spain in the changed diplomatic circumstances of 1622 to conclude the negotiations for the Spanish Match. His authority was undermined when Prince Charles and Villiers (marquess and presently duke of Buckingham) arrived in Madrid in March 1623.
Bristol only emerged from political obscurity in the autumn of 1640, when he was one of the delegates who negotiated the treaty of Ripon with the Covenanters, a service which probably explains his restoration to the Privy Council in February 1641.