The trial of Eleanor Cobham ( She was tried and convicted of practising witchcraft against the King in an attempt to retain power for her husband. She was exiled and imprisoned for life), his second wife, was a great blow to Gloucester's influence, and this was still further reduced when, in 1442, Henry VI came of age, and the protectorate was at an end. Suffolk supplanted Gloucester as the chief adviser of the crown
Gloucester was suddenly arrested on Feb. 18, 1447, at Bury St. Edmund's, and placed under arrest, and five days after was found dead in his bed. At this point in time it is impossible to decide on the cause of his death. Poison is a possibility introduced by some person who hoped thereby to ingratiate himself with the court party, or it may (as popular legend asserted), have been caused by the orders of the Duke of Suffolk. There is nothing in the historic record to connect it with Cardinal Beaufort, and there is a strong reason for believing that it arose from natural causes, i.e. most probably a stroke