[12] The death of his wife led Clarence to believe that her lady-in-waiting and midwife, Ankarette Twynyho, and a servant, had poisoned her and his son with a "venomous drink of ale".

[13][page needed] He had them brought to trial, found guilty and executed on very slim evidence by a rigged court in April 1477.

The following year, the late King's marriage was declared invalid by the statute Titulus Regius, making his children illegitimate.

[10] Edward was briefly displayed in public at St Paul's Cathedral in 1487 in response to the presentation of the impostor Lambert Simnel as the "Earl of Warwick" to the Irish lords.

[21] Margaret remained dynastically important to the new Tudor dynasty due to her Yorkist lineage and unquestionably noble blood.

It has been argued by historians such as Tracy Borman that this was intended to undermine her status, weaken her claim to the English throne and ensure that she was married to a loyal supporter.

[7] Horace Walpole later reflected in his correspondence that "Henry had married her to the insignificant Sir Richard Pole who is called a Welsh Knight".

He was appointed as a Knight of the Garter in 1499, and he was entrusted with the prestigious role of Chamberlain for Arthur, Prince of Wales, the heir apparent to the throne.

[4] She borrowed £40 from Henry VII to pay for Pole's funeral,[6] with Charles Somerset, 1st Earl of Worcester, standing in surety for the loan.

[4] She took lodgings at Syon Abbey, on the banks of the River Thames, along with her daughter Ursula and youngest son Geoffrey, as guests of the Bridgettine nuns.

[6] She devoted her third son, Reginald Pole, to the Church, relinquishing all financial responsibility for him and sending him to the Carthusian Monastery at Sheen to be educated with the monks of the Charterhouse.

[6] Then on 4 February 1512, after Margaret's petition to the King,[6] her brother's attainder was reversed and an Act of Parliament restored the Earldom of Salisbury to her.

[7] Gentian Hervet translated Erasmus' de immensa misericordia Dei (The Great Mercy of God) into English for her.

[9] Her first son, Henry Pole, was created Baron Montagu in 1514, another of the Neville titles in its first creation,[citation needed] speaking for the family on Margaret's behalf in the House of Lords.

[4] Margaret and her son Henry pressed Arthur's widow to take a vow of perpetual chastity to preserve her inheritance for the Pole children.

[citation needed] Ursula's husband was created 1st Baron Stafford by King Henry's son and successor, Edward VI in 1547.

[42] Margaret's third son, Reginald Pole, was educated at Magdalen College, Oxford, and studied abroad at the University of Padua in Italy, with a £100 stipend from the king.

[44] Margaret's youngest son, Geoffrey Pole, married Constance, daughter of Edmund Pakenham, and inherited the estate of Lordington in Sussex.

[51] Margaret was initially amongst a group of high ranking noblewomen who openly opposed the King's divorce from Catherine of Aragon.

[26] In 1531, Margaret's son Reginald had warned of the risks if Henry should divorce Queen Catherine and marry Anne Boleyn.

[43] Chapuys suggested to Emperor Charles V that Reginald should marry Henry VIII's daughter Mary and combine their dynastic claims.

[43] He replied to a letter that he had received from Henry VIII with a copy of his own pamphlet, pro ecclesiasticae unitatis defensione, commonly known as De unitate.

The pamphlet denied both royal supremacy and Henry's position on marriage to a brother's wife, and referred to him as "a robber, murderer and greater enemy to Christianity than the Turk".

[12] After Anne Boleyn was arrested and executed, Margaret was permitted to return to court, albeit briefly, to serve the new Queen Jane Seymour.

[58] He said that Exeter had been party to his correspondence with Reginald and he shared details about Henry, Lord Montagu's dislike of the King and his policies.

"[26] Margaret was nevertheless accused of abetting her sons[7] and of having “comytted and p[er]petrated div[er]se and sundry other detestable and abominable treasons.”[59] She was interrogated for three days by William FitzWilliam, Earl of Southampton, and Thomas Thirlby, Bishop of Ely,[52] while imprisoned at Cowdray House, Midhurst, West Sussex, which was Fitzwilliam’s home.

[60] The King convinced himself that he had escaped death by a narrow margin and informed Emperor Charles V that for ten years Exeter and Montagu had planned to murder him.

[57] Her estate, including Warblington Castle, was temporarily awarded to Sir Thomas Wriothesley, 1st Earl of Southampton and the king's personal secretary.

[61] As part of the evidence for the bill of attainder, Cromwell produced an embroidered tunic bearing the Five Wounds of Christ, and heraldic symbols supposedly symbolising Margaret's support for the Church of Rome and the rule of her son Reginald with the King's Catholic daughter Mary.

Because the chief executioner had been sent north to deal with rebels, the execution was performed by "a wretched and blundering youth who hacked her head and shoulders to pieces in the most pitiful manner".