The alteration in the personnel of the Tower was almost immediately followed by severe illness on the part of the prisoner. The close confinement to which he was subjected, with the lack of exercise, could hardly have been the cause of such a violent sickness. It looked more as if it had been brought about by something he had eaten or drunk. By this time the conviction he had tried to resist, that Rochester was meanly sacrificing him, became definite. Overbury is hardly to be blamed if he came to a resolution to be revenged on his one-time friend by bringing him to utter ruin. King James had been so busy in the Essex nullity suit, had gone to such lengths to carry it through, that if it could be wrecked by the production of the true facts he would be bound to sacrifice Rochester to save his own face. Sir Thomas had an accurate knowledge of the King's character. He knew the scramble James was capable of making in a difficulty that involved his kingly dignity, and what little reck he had of the faces he trod on in climbing from a pit of his own digging. By a trick Overbury contrived to smuggle a letter through to the honest Archbishop Abbot, in which he declared his possession of facts that would non-suit the nullity action, and begged to be summoned before the commission. Overbury was getting better of the sickness which had attacked him when suddenly it came upon him again. This time he made no bones about saying that he had been poisoned. Even at the last Overbury had taken care to give Rochester a chance to prove his fidelity. He contrived that the delivery of the letter to the Archbishop of Canterbury should be delayed until just before the nullity commission, now augmented by members certain to vote according to the King's desire, was due to sit again. The Archbishop carried Overbury's letter to James, and insisted that Overbury should be heard. The King, outward stickler that he was for the letter of the law, had to agree. On the Thursday of the week during which the commission was sitting Overbury was due to be called. He was ill, but not so ill as he had been. On the Tuesday he was visited by the King's physician. On the Wednesday he was dead. Now, before we come to examine those evidences regarding Overbury's death that were to be brought forward in the series of trials of later date, that series which was to be known as "the Great Oyer of Poisoning," it may be well to consider what effect upon the Essex nullity suit Overbury's appearance before the commission might have had. It may be well to consider what reason Rochester had for keeping his friend in close confinement in the Tower, what reason there was for permitting Northampton to impose such cruelly rigorous conditions of imprisonment.