The 1st Earl of Essex died in The Tower of London (13 July 1683), having been convicted of participation in the Rye House Plot against the King and his brother, and was said to have been discovered in his chamber with his throat cut whilst a prisoner awaiting execution for treason. According to Britton The Earl of Essex's death, by suicide, was controversial:-

Lawrence Braddon., Gent of the Middle Temple states himself 'upwards of 5 years persecuted or imprisoned for endeavouring to discover this murther the third day after the same was committed' The Dictionary of National Biography entry for Braddon says:-

“ When the Earl of Essex died in the Tower in 1683, Braddon adopted the belief that he had been murdered, and worked actively to collect sufficient evidence to prove the murder. He set on foot inquiries on the subject in London, and when a rumour reached him that the news of the earl's death was known at Marlborough on the very day of, if not before, the occurrence, he posted off thither. When his action became known at court, he was arrested and put under restraint. For a time he was let out on bail, but on 7 Feb. 1683-4 he was tried with Mr. Hugh Speke at the king's bench on the accusation of conspiring to spread the belief that the Earl of Essex was murdered by some persons about him, and of endeavouring to suborn witnesses to testify the same. Braddon was found guilty on all the counts, but Speke was acquitted of the latter charge. The one was fined 1,000l. and the other 2,000l., with sureties for good behaviour during their lives. Braddon remained in prison until the landing of William III, when he was liberated. “

His death was attributed, quite groundlessly, to Charles and James, and the evidence points clearly if not conclusively to suicide, his motive being possibly to prevent an attainder and preserve his estate for his family. Gilbert Burnet, who knew Essex well, accepted that his death was suicide, since Essex had often spoken of suicide as an honourable course. Lord Ailesbury wrote: "The Earl asked very coldly for a razor to cut his nails, and being accustomed so to do gave no manner of suspicion. He went into a small closet," where his servant afterward found him "dead and wallowing in blood"... the assumption being that the reason he "cutt his own throat with a knife" was because of his knowledge of the Rye House Plot. The King, who seemed genuinely distressed at the news of his death, remarked that Essex should have known that he would spare him, "for I owe him a life", Essex's father having died in the service of Charles I.