KNOLLYS, WILLIAM, Earl of Banbury (1547–1632), second but eldest surviving son of Sir Francis Knollys [q. v.], was born in 1547, and was educated in early youth by Josceline or Julius Palmer, who fell a victim to the Marian persecution in 1556. William performed his first public service as captain in the army which was sent to repress the northern rebellion in 1569. He was elected M.P. for Tregony in 1572, and for Oxfordshire in 1584, 1593, 1597, and 1601. In November 1585 Queen Elizabeth sent him as ‘one that appertaineth to us in blood’—his mother was the queen's first cousin—to James VI of Scotland to assure him that she had no intention of aiding the banished Scottish lords (Corresp. of Eliz. and James, Camd. Soc., p. 23). In the following January he accompanied Burghley's son Thomas in the expedition to the Low Countries under Leicester (Leycester Corresp., Camd. Soc., p. 58), and was knighted by Leicester on 7 Oct. 1586. He was colonel of the Oxford and Gloucester regiments of foot which were enrolled to resist the Spanish Armada in 1588, and was created M.A. of Oxford on 27 Sept. 1592.
Elizabeth extended to him the favour that she had shown his father, and on the latter's death in 1596 and the consequent changes in court offices, Knollys was made comptroller of the royal household and a privy councillor (30 Aug. 1596). He inherited" his father's estates in Oxfordshire and Berkshire, and became joint lieutenant of those counties on 4 Nov. 1596, sole lieutenant in July 1601, and lord-lieutenant 22 March 1612-13. He was a commissioner to arrange a peace between the Dutch and the emperor in August 1598, and was granted the reversion to the office of constable of Wallingford Castle 8 Feb. 1601. At the final trial of the Earl of Essex (January 1601) he entered the witness-box to deny the statement of the defence that Sir Robert Cecil had in private conversation acknowledged the infanta's title to the crown of England (Cecil, Corresp., Camd. Soc., p. 70 n.),and in August 1601 he entertained his sovereign at his house at Caversham, and in May 1602 at his residence in St. James's Park. On 22 Dec. 1602 he succeeded Roger, lord North, as treasurer of the royal household, a position which his father had filled before him.
On James I's accession Knollys retained all his offices, and was further created, on 13 May 1603, Baron Knollys of Rotherfield Greys. He became cofferer of the household to Henry, prince of Wales, in 1606. In May 1613 he represented his cousin the Earl of Essex in the abortive conference held at Whitehall to arrange a separation between the earl and the earl's wife, Frances, who was a sister of Knollys's second wife. In 1614 he proved his loyalist zeal by putting down the names of persons as willing to subscribe to the benevolence of that year without consulting them. He acted as commissioner of the treasury from 24 Jan. to 11 July 1614, and was made master of the court of wards on 10 Oct. following. On 24 April 1615 he was elected a knight of the Garter, and was promoted in the peerage to the viscountcy of Wallingford on 7 Nov. 1616. In the following month he resigned the treasurership of the household. Wallingford's influence at court was at the time somewhat imperilled by his connection with the Howards, his wife's family. His sister-in-law Frances, then Countess of Somerset, was placed on her trial for the murder of Overbury in 1615, and all her kinsfolk were suspected of complicity. But the chief witness against the Howards, Mrs. Turner, had to admit, respecting Wallingford, ‘if ever there was a religious man, it was he.’ When Thomas Howard, earl of Suffolk [q. v.], his father-in-law, fell into disgrace in 1618, his wife openly attributed her family's misfortunes to Buckingham's malice; the words were reported to the king, who declared that he did not wish to be further served by the husband of such a woman. Wallingford was accordingly forced to resign the mastership of the wards (December 1618). He gradually recovered his position, and in April 1621 took a leading part in the House of Lords in the case of Bacon, insisting that the chancellor should furnish a full answer to the charges brought against him. In 1622 he and his wife's relatives patched up a reconciliation with Buckingham, and Wallingford sold to him his London residence, Wallingford House, for 3,000l.
The earldom of Banbury was conferred on Knollys by Charles I on 18 Aug. 1626, possibly, as Mr. Gardiner suggests, in order to complete the king's and Buckingham's reconciliation with the Howard family. The patent contained a clause that ‘he shall have precedency as if he had been created the first earl after his Majesty's accesse to the crowne.’ The lords resisted this grant of precedency as an infringement of their privileges, but when a committee met to consider the question, Charles sent a gracious message, desiring ‘this may pass for once in this particular,
