Sir William Knyvett (1441/2 – 2 December 1515) was an English knight in the late Middle Ages. He was the son of John Knyvett and Alice Lynne, the grandson of Sir John Knyvett, and assumed the titles of Sheriff of Norfolk & Suffolk, Burgess of Melcombe, Bletchingley, & Grantham, Constable of Rising Castle.

Life Sir William married three times. The first was to Alice Grey (d. 1474), daughter of John Grey, Esq., of Kempston, eldest son of Reginald Grey, 3rd Baron Grey de Ruthyn by his second wife, Joan Astley; by whom he had issue. His second marriage was to Lady Joan Stafford, daughter of Humphrey Stafford, 1st Duke of Buckingham and Lady Anne Neville, by whom he had issue. His final marriage was to Lady Joan Courtenay (d. 8 February 1501), widow of Sir Roger Clifford, and daughter of Thomas de Courtenay, 5th Earl of Devon, a friend of York, and his wife, Lady Margaret Beaufort; they had no issue.

He was one the executors of the will of his uncle-by-marriage, Avery Cornburgh.

In 1483, he was attainted by the name of Sir Will. Knevet, Knt. of Bukenham, conjurer, together with the Earl of Richmond and John, Earl of Oxford in the parliament summoned the 25 January 1st Richard III, as being partakers with Henry, Earl of Richmond (afterwards Henry VII).

In 1482 his sister Elizabeth had died under mysterious circumstances. Roger Virgoe writes: In 1482 an inquest was held on the body of Elizabeth Knyvett, spinster, of Buckenham Castle, who had died in the Marshalsea Prison. The inquest found that she had died by 'divine visitation'. i.e. of natural causes, but it is difficult to understand how a powerful family like the Knyvetts could have allowed a daughter and sister to be imprisoned: it must surely have been a serious matter.Elizabeth was one of his three sisters, the other two being Margaret and Christian, who married Henry Colet.

Sir William Knyvett was one of the Knights Bachelor at the coronation of Elizabeth of York in 1487.

Sir William Knyvett died 2 December 1515. In his will dated 18 September 1514 and proved 19 June 1516 he requested to be buried in the church of Wymondham, Norfolk. As executors Knyvett appointed his son, Edward, together with Lord Fitzwalter, Sir Thomas Wyndham, the lawyer, Francis Moundford, and his servants, Richard Banyard and John Kensey. As overseer he appointed 'my most singuler good and gracious lord, my lord of Buckingham.' Edward proved the will on 19 June 1516.

At New Buckenham, in 1888, the following inscription was found on a brass, loose in the Church Chest:To the memory of Alice, wife of William Knyvet, Esq., dau. of John Grey, son of Reginald Grey, Lord of Rythin, who died 4 April 1474.A century before it had been on a flat stone.

Issue His children by his first wife, Alice Grey (d. 4 April 1474), were:

Sir Edmund Knyvett (d.1504Sir Edmund Knyvett married Eleanor Tyrrell (died 1514), the daughter of Sir William Tyrrell of Gipping, Suffolk, and sister of Sir James Tyrrell. They had six sons and three daughters, including Edmund Knyvett (died 1 May 1539), esquire, who married Joan Bourchier, the only surviving child of John Bourchier, 2nd Baron Berners. Sir Edmund Knyvett was drowned at sea in 1504; .) of Buckenham, who married Eleanor Tyrrell, the daughter of Sir William Tyrrell of Gipping, Suffolk by Margaret, daughter of Robert Darcy, knight. Eleanor was sister of Sir James Tyrrell.Richardson, Douglas (2011). Magna Carta Ancestry: A Study in Colonial and Medieval Families, ed. Kimball G. Everingham. II (2nd ed.). Salt Lake City. p. 322. Sir Edmund Knyvett, his eldest son by his first marriage, was partly disinherited by his father, who left Buckenham Castle and other properties to Sir Edward Knyvett, the eldest son of his second marriage to Joan Stafford.Sir Edward Knyvett’s heir was his nephew, Robert Knyvet, son of his brother, Charles Knyvett (died before 22 October 1528). Robert Knyvett was slain during the suppression of Kett's Rebellion in 1549. Children of Sir Edmund Knyvett and Eleanor Tyrrell: Sir Thomas Knyvett of Buckenham, Norfolk (c. 1485 – 10 August 1512) who married Muriel Howard (d.1512), the widow of John Grey, 2nd Viscount Lisle, by whom she was the mother of Elizabeth Grey, Viscountess Lisle, who was at one time betrothed to Charles Brandon, 1st Duke of Suffolk and was the wife of Henry Courtenay. Muriel Howard was the daughter of Thomas Howard, 2nd Duke of Norfolk, and Elizabeth Tilney. Edmund Knyvett (d. 1 May 1539), esquire, sergeant porter to King Henry VIII, who married Joan Bourchier (d. 17 February 1561/2), the only surviving child of John Bourchier, 2nd Baron Berners, and had: John Knyvett of Plumstead (1517–1561), who m. Agnes, daughter of Sir John Harcourt of Stanton Harcourt, Oxfordshire, by settlement dated 14 February 1537, and had: Thomas Knyvett (1539–1616) of Ashwellthorpe, de jure 4th Baron Berners, High Sheriff of Norfolk from 1579, m. Muriel Parry, daughter of Sir Thomas Parry, Comptroller of the Household to Queen Elizabeth I, and had: Sir Thomas Knyvet (d. 1605), of Ashwellthorpe, Norfolk and Stradbroke Katherine Knyvett, Lady Paston, one of the writers of the Paston Letters Muriel Knyvett, who married Sir Edmond Bell, as his second wife Mary Knyvett, who married Sir Thomas Holland of Quidenham, Norfolk, and had Sir John Holland, 1st Baronet Abigail Knyvett, m. Sir Edmund Moundeford of Mundford and Hockwold, Norfolk the grandson of Francis Mountford, as his second wife. From his first marriage he had Sir Edmund Moundeford (1596 – May 1643), who left much of his inheritance to his half-sister, Abigail's daughter Elizabeth Edmund Knyvett Henry Knyvett Abigail Knyvett (d. 1623), who married Martin Sedley of Morley, Norfolk (1531–1609/10), as his second wife, by settlement dated 1577 Elizabeth Knyvett, who married Anthony Ashfield Possibly the Rose Knyvett who married Michael Beresford. This has been discounted because of the arms registered in visitations and which are on display on the tomb of her daughter Bennet (also a Knyvett name), as Rose's coat of arms is given as Gules, three plates charged with a cinquefoil sable, unlike this Knyvett family, whose arms are Argent, a bend sable engrailed within a border of the same. Rose was the grandmother of Sir Tristram Beresford, 1st Baronet William Knyvett (buried 30 June 1612), second son, married Dorothy (buried 2 March 1616), daughter of Robert Themilthorp of Tunstead, and by will dated Nov. 26, 1594, ordered his body to be buried in the church of Fundenhale, where he lived, leaving two sons and two daughters: John Knyvet of Fundenhale, his eldest son, married Joan daughter of Robert Browne of Tacolneston, and had John Knyvet of Fundenhale, who by his wife Anne had John, who married secondly Joanna Sutton, and had William Knyvet, Esq. of Fundenhale, a later coroner for the county of Norfolk, from whom descended Charles Knyvett and William Knyvett Thomas (baptised 21 July 1563 – buried 12 November 1595), the second son, died without issue Edmund (baptised 4 December 1565) Henry (baptised 9 October 1569) Joanna (baptised 30 March 1561) Muriel, the eldest (surviving) daughter, married to Jeffry Abbs, and had issue Amphillis, the second (surviving) daughter, married 16 April 1611 to William Baldwin Anne, married to Mr. Johnson (d. bef. 1612), and left issue Margareta (born 1573) Edmund Knyvett. His mother surrendered her manor of Gately in 1551 jointly to her sons William and Edmund Knevet. He married firstly Elizabeth, daughter of Charles Knyvett, and secondly Elizabeth Gooday on 3 December 1563. He had issue from both wives Thomas, married Mary Wolverton of Wolverton in Suffolk Rose Knyvett (d. 1587/8), married as his second wife Oliver Reims of Burnham Debden in Norfolk and of Hempton by Fakenham Alice, wife of Oliver Shiers of Wreningham Christian, wife to Thomas Foster Katherine Knyvett (d. 1595/6), married firstly John Walpole of Harpley & Colkirk in Norfolk (d. 1557/8), Serjeant-at-law, Gray's Inn. M.P. for Lynn 1553, and secondly Thomas Skarlett of Harpley, Gentleman, the executor of the will of her first husband. Elizabeth, married Francis Bohun of Tressingfield in Suffolk Anne, married Edmund Thimelthorpe of Worsted in Norfolk Christopher Knyvett. Christopher Knyvett, the third brother in his family, is particularly noteworthy because he and his wife from Brabant are believed to be depicted in the 'Ashwellthorpe Triptych' housed at Norwich Castle Museum. Christopher likely followed his elder siblings to the court of Henry VIII at the beginning of the new reign, establishing his presence there by October 1512 when he was dispatched as an envoy to the court of Margaret, Duchess of Savoy, the regent of the Netherlands. Margaret’s court was renowned for its culture, nobility, and learning, attracting English ladies such as Anne Boleyn for their courtly education. Although it’s tempting to connect Christopher’s marriage to the 'daughter and heir of the lord of Ashe near Brussels' and the painting to this diplomatic mission, he was probably quite young at that time. It's more plausible that the marriage occurred due to a later mission, as the painting is dated '1519'. While there is no direct evidence of Christopher being in the Netherlands after 1512, it seems highly probable, especially since his brother Anthony was sent there on a mission in 1518. If Catherine van Assche was indeed an heiress, as genealogical records suggest, this marriage was an exceptionally advantageous match for a younger son without clear prospects of acquiring land. It is indeed true that he appeared to enjoy favor at Court, and from 1515, he received an annual wage of £20 for his role in the Household. It's likely that he joined the King during the siege of Tournai in 1513, and in 1515, he and his brothers, James and Anthony, were granted the lands and possessions of two 'rebels' in that city. However, whether they benefited financially from this grant remains uncertain. There is no additional evidence of any other grants or promotions in the King's service. Nonetheless, his prospects improved significantly at the end of 1519 when he inherited the reversion of a modest yet substantial estate in Northamptonshire from his cousin, John Colet, Dean of St. Pauls. On 14 November of that year, he was granted control of the estate, subject to a rent of 20 marks per year payable to Colet's mother, Christian Colet, who was Christopher's great-aunt. It's possible that Christopher's marriage and the commissioning of the Triptych were linked to his newfound status as a small landowner, although there is no evidence to support this. No further mentions of Christopher have been found following the payment of his half-year's wages in early 1520, and it is likely that he died later that year or shortly thereafter. If he had moved to live on his wife's estates in Brabant, it would be difficult to explain how the Triptych ended up at his brother Edmund's residence in Ashwellthorpe. There is no evidence that he had any children, and his wife's fate remains unknown. James Knyvett. James, the fourth brother, had joined his older siblings at Court by 1510 when he received livery as the King's servant. Under the command of his brother, Sir Thomas, and the Howards, he was actively involved in the French Wars of 1512–14, initially as captain of the 'Margaret of Topsham' and later the 'Mary Cradok'. In October 1513, he received a special payment of £10 for his skirmishing with the French. Alongside his brothers, he was awarded lands and goods at Tournai in 1515. In 1516, he attended the King with two of his brothers at jousts of honor. However, there are no further records of him, and he likely died soon after, as he is not mentioned alongside his brothers as remainderman in John Colet's will made in August 1519.