The story of the Countess of Somerset, who was tried with others for the murder of Sir Thomas Overbury in the reign of James I, forms an interesting episode in the history of romantic poisoning. Robert, Earl of Essex, son of Queen Elizabeth's favourite, and who afterwards became Commander-in-chief of the Parliamentary forces, married, at the age of fourteen, Frances Howard, a younger daughter of the Earl of Suffolk, the bride being just a year younger than her husband. The match had been arranged and brought about through the influence of relatives, who thought it expedient that the youthful bridegroom should be sent off to travel on the Continent immediately after the marriage had taken place, and he remained away for three or four years. During this period the countess, who was brought up at court, developed into a very beautiful woman, but seems to have been equally unprincipled and capricious. On the return of the earl from his travels, she shrank from all advances on his part, and showed the utmost repugnance to her husband on all occasions. Their dispositions were entirely different. He loved retirement, and wished to live a quiet country life, while she, who had been bred at court, and accustomed to adulation and intrigue, refused to leave town. The King about this time had a number of young men of distinguished appearance and good looks attached to the court, and of these, one Robert Carr, at length became an exclusive favourite. Between him and the self-willed young countess there sprang up an attachment, which, at least on her side, amounted to infatuation. Her opportunities for meeting her lover were short and rare, and in this emergency she applied to a Mrs. Turner, who introduced her to Dr. Forman, a noted astrologer and magician at that time, and he, by images made of wax, and other devices of the black art, undertook to procure the love of Carr to the lady. At the same time he was also to practise against the earl in the opposite direction. These measures, however, were too slow for the wayward countess, and having gone to the utmost lengths with her inamorata, she insisted on a divorce, and a legal marriage with him.
One of Carr's greatest friends was Sir Thomas Overbury, a young courtier and a man of honour and kindly disposition. He was much against this intimacy, and besought his friend to break it off, assuring him it would ruin his prospects and reputation if he married the lady. Carr unwisely made this known to the countess, who at once regarded Overbury as a bitter enemy, and resolved to do what she could to overthrow him. The pair plotted together with evident success, for the unfortunate Sir Thomas was shortly afterwards committed to the Tower by an arbitrary mandate of the King; next, he was not allowed to see any visitors; and, finally, his food was poisoned, and, after several unsuccessful attempts on his life, he at last died from the effects of poison. Cantharides, nitrate of silver, spiders, arsenic, and last of all, corrosive sublimate, are said to have been administered in turn to this unfortunate individual. Meanwhile, the countess obtained a divorce from her husband on the ground of impotency, and married Carr, who was soon after made Earl of Somerset by King James.