His ambition to marry his royal mistress, who, shrewd woman as she was, seems to have had no insight into his unscrupulous character, was the cause of his moving every human obstacle from his path by insidious methods. The murder of his wife Amy Robsart was the first of a long series of murders, carried out, doubtless, at his instigation. He was next suspected of causing the death of Lord Sheffield, of whose lady he was an admirer. The Earl of Essex is said to have been another victim. His death is described in the language of the time as having been due to "an extreme flux caused by an Italian Receit, the maker whereof was a surgeon that then was newly come to my Lord from Italy, a cunning man and sure in operation. The inventor of this recipe was known as one Dr. Julio, who was said to be able to make a man dye in what manner of sickness you will." The death of the Earl of Essex took place when on his way home from Ireland, with the object of revenging himself on the Earl of Leicester for his domestic wrongs. The next victim is said to have been Cardinal Chatillian, who, having accused the earl of preventing the marriage of the queen to the King of France, was journeying back to Dover, when he was taken suddenly ill and died in Canterbury. Sir Nicholas Throgmorton, a wealthy city magnate and a tool of the earl's, whom, 'tis said, he used to thwart the doings of the Lord Treasurer, Sir William Cecil, was another victim. Having heard that Sir Nicholas was revealing some of his secrets, he invited him one night to supper at his house in London, and at supper time hurriedly went to the court, to which he said he had been called suddenly by her Majesty. Sir Nicholas proceeded with the meal in his absence, and soon after was seized with a violent vomiting, from which he never recovered. According to an old chronicler, "The day before his death he declared to a dear friend, all the circumstances and cause of his complaint, which he affirmed plainly to be poison given him in a sallet at supper, inveighing most earnestly against the earl's cruelty and bloody disposition, and affirming him to be the wickedest, most perilous and perfidious man under heaven." The chronicler continues: "And for his art of poisoning, it is such now, and reaching so far, as he holdeth all his foes in England and elsewhere, as also a good many of his friends, in fear thereof, and if it were known how many he hath despatched in that way would be marvellous to posterity.