Edward Seymour, the eldest son of the Protector Somerset, incurring the Queen's unrelenting displeasure. As the ceremony had been performed by a priest who was never subsequently identified, and the only witness was Seymour's sister, Lady Jane Seymour, who died shortly after the marriage, the Queen was able to treat the marriage as though it had never taken place, and on 12 March 1563, she obtained a declaration that the marriage was invalid and that Edward Seymour, Viscount Beauchamp, Katherine's eldest son by Seymour, was illegitimate. Both Katherine and her husband were confined to the Tower, and they were later held under house arrest. Marriage Despite the disastrous consequences of her sister Katherine's secret marriage, Mary also now married without the Queen's permission. On 16 July 1565, while the Queen was absent attending the marriage of her kinsman, Sir Henry Knollys (d. 21 December 1582), and Margaret Cave, the daughter of Sir Ambrose Cave, Mary secretly married the Queen's sergeant porter, Thomas Keyes, son of Richard Keyes, esquire, of East Greenwich, Kent, by Agnes Saunders, the daughter of Henry Saunders of Ewell, Surrey. Having learned from her sister's experience, Mary took the precaution of having three of her cousins attend as witnesses, her childhood friend, Mary Willoughby, now the wife of Sir Matthew Arundell, and two of the daughters of Lady Stafford. The marriage was an unsuitable one for many reasons. Keyes was from a minor gentry family in Kent, was more than twice Mary's age, and was a widower with six or seven children. Moreover, Mary was described by the Spanish ambassador as 'little, crook-backed and very ugly', while Keyes stood 6 feet 8 inches tall. Sir William Cecil wrote to Sir Thomas Smith that 'The Sergeant Porter, being the biggest gentleman of this court, has married secretly the Lady Mary Grey, the least of all the court ... The offence is very great'. House arrest Mary and her husband never saw each other again. The Queen confined Mary to house arrest with William Hawtrey (d. 1597) at Chequers in Buckinghamshire, where she remained for two years, while Keyes was committed to the Fleet. In August 1567, Mary, still under house arrest, was sent to live with her step-grandmother Katherine, Duchess of Suffolk, whom Charles Brandon, 1st Duke of Suffolk, had married after the death of Mary's grandmother Mary Tudor. The Duchess wrote to Cecil expressing shock at the