Jonson declined all further intercourse with Overbury (Jonson, Conversations with Drummond, p. 16).
Whatever may have been Overbury's opinion of Lady Essex's fitness to become Rochester's mistress, he had no doubt whatever of her unfitness to become Rochester's wife. As soon, therefore, as she had succeeded in divorcing her husband, the Earl of Essex, and had avowed her intention of marrying Rochester, Overbury passionately entreated the latter to break with her. But the lady had gained complete control of her lover, and Rochester, apparently for the first time in his life, resented his friend's advice. Overbury persisted in his unwelcome counsel, and, according to his father, directed Rochester's attention to his poem on ‘A Wife,’ ‘to prove that Rochester could make a better choice than a divorced countess.’ Rochester, goaded by the taunts of his resolute mistress, was roused to retaliate, but the anticipation of an abiding breach with Overbury alarmed him. He was apparently conscious that Overbury was in possession of some information which, if revealed, might injure or even ruin him. In Scotland it was hinted that the mysterious secret concerned an attempt which Overbury and Rochester had jointly made to murder Prince Henry. But at any risk Rochester resolved to relieve himself, at least temporarily, of his friend's company. The unscrupulous Earl of Northampton, who was grand-uncle of Lady Essex, and had set his heart on the match, strongly recommended Overbury's removal from a scene in which he could work mischief. Accordingly James I was induced to offer Overbury a diplomatic appointment. Winwood asserts that he was invited to become ambassador in France or in the Low Countries (Winwood, Memorials, iii. 447, 453); but Bishop Goodman states that ‘some meaner place’ was suggested, and John Chamberlain the letter-writer and Sir Simonds D'Ewes mention Russia (Notes and Queries, 6th ser. v. 350–1). Every bait was held out to lead him to accept the offer. The lord chancellor and the Earl of Pembroke are said to have hinted at the king's command that employment abroad was to be the prelude of high office at home, and the post of treasurer of the royal household was mentioned as likely to fall at an early date into his hands. But Overbury steadily refused to entertain the proposal, and his obstinacy excited adverse criticism at court. Both the king and queen viewed him with little favour. The king, who was jealous of the affection long shown him by the favourite Rochester, was reported to resent ‘the stiff carriage of his fortune,’ and to nourish ‘a rooted hatred in his heart towards him.’ At the same time the queen was credited with harbouring some ill-feeling because she imagined he had once laughed at her disrespectfully while walking with Rochester beneath her window at Greenwich Palace; Overbury, it seems, had overheard her speak of him as Rochester's ‘governor,’ and the remark moved him to laughter. Lady Howard's friends naturally neglected no opportunity of emphasising Overbury's intractability. The gossip ran that ‘there was much ado’ to save Overbury from a ‘public censure of banishment and loss of office’ (Southampton to Winwood, 4 Aug. 1613). But Rochester and Northampton came to an understanding that his sojourn for a few months in the Tower would satisfy the situation. His withdrawal from public life would at any rate enable Rochester to proceed with his marriage without molestation. Consequently, on 26 April 1613, ‘about six o'clock in the evening, Sir Thomas Overbury was from the council-chamber conveyed by a clerk of the council and two of the guard to the Tower, and there by warrant consigned to the lieutenant as close prisoner.’
The incident produced almost a panic at court. Wotton, who witnessed the arrest, wrote that the ‘quality and relation of the person bred in beholders infinite amazement.’ The antecedent circumstances were not generally known, but Wotton showed exceptional sagacity when he prophesied that Overbury ‘shall return no more to this stage.’
No proof has been adduced that Rochester regarded Overbury's imprisonment as other than a temporary expedient. Rochester's intended bride, however, viewed it in another light. There seems no question that she at once determined to murder Overbury in the Tower. She had already suggested his assassination to one Sir Davy Wood, who believed that Overbury had done him some injury. She had even promised Wood a reward of 1,000l. as soon as the deed was done. But Sir Davy made it a condition that the countess should secure a pardon from Rochester before he entered on the design, and, as she was unable to procure such an instrument, the negotiation went no further. After Overbury's committal, her granduncle Northampton, although he may not have been wholly in her confidence, readily aided her in the preliminary steps of her plot against Overbury's life, and did not too closely inquire into her aims. By Northampton's influence, she contrived the dismissal of the lieutenant of the Tower, Sir William Waad, a man of unbending virtue, from whom it was hopeless to