Following Catherine of Aragon's death on the afternoon of 7th January 1536, her body was prepared for burial by a chandler in her household, whose job it would have been to embalm her body. Sir Edmund Bedingfield and Sir Edward Chamberlain wrote to Thomas Cromwell from Kimbolton on 7th January about the arrangements they had made:
"Sir, the groom of the chandlery here can cere her [...] and further I shall send for a plumber, to close the body in lead, the which must needs shortly to be done." State Papers, King Henry VIII, Volume I,p452
"Cere" meaning to disembowel and embalm.
Eustace Chapuys, in a letter to Charles V on 21st January 1536, wrote of Catherine of Aragon's body being "opened" and examined following her death. She was not examined by a physician, but by a servant of her household, the chandler. It was usual for a chandler to embalm bodies ready for burial, but he would not have been a medical expert in any way.
Here is Chapuys' report:
"The Queen died two hours after midday, and eight hours afterwards she was opened by command of those who had charge of it on the part of the King, and no one was allowed to be present, not even her confessor or physician, but only the candle-maker of the house and one servant and a "compagnon," who opened her, and although it was not their business, and they were no surgeons, yet they have often done such a duty, at least the principal, who on coming out told the bishop of Llandaff, her confessor, but in great secrecy as a thing which would cost his life, that he had found the body and all the internal organs as sound as possible except the heart, which was quite black and hideous, and even after he had washed it three times it did not change color. He divided it through the middle and found the interior of the same color, which also would not change on being washed, and also some black round thing which clung closely to the outside of the heart. On my man asking the physician if she had died of poison he replied that the thing was too evident by what had been said to the Bishop her confessor, and if that had not been disclosed the thing was sufficiently clear from the report and circumstances of the illness." LP x. 141
The description of the heart gave rise to the idea that Catherine had been poisoned, particularly as her illness had been said to worsen after drinking a draught of Welsh ale:
"The Queen's illness began about five weeks ago, as I then wrote to your Majesty, and the attack was renewed on the morrow of Christmas day. It was a pain in the stomach, so violent that she could retain no food. I asked her physician [de la Soa] several times if there was any suspicion of poison. He said he was afraid it was so, for after she had drunk some Welsh beer she had been worse, and that it must have been a slow and subtle poison for he could not discover evidences of simple and pure poison; but on opening her, indications will be seen." Chapuys to Charles V, 9 January 1536, LP x. 59
Chapuys and Miguel de la Soa, Catherine's physician were convinced that Catherine had been poisoned.
However, as Giles Tremlett and Patrick Williams point out in their biographies of Catherine, the description of the heart actually suggests cancer:
"A secondary melanotic sarcoma was almost certainly to blame." Giles Tremlett (Afterword, Catherine of Aragon: Henry's Spanish Queen)
"...if this unscientific analysis has any relevance it would suggest that Katharine died of a cancerous metastatic melanoma." Patrick Williams, Katharine of Aragon, p375. In his notes, Williams thanks Dr Veronica Sprott for her advice.
J.J. Scarisbrick, in his book "Henry VIII", also wrote that the chandler's description "is conclusive evidence that she died of cancer. His description of the 'black round body' and her blackened heart exactly fits that of a secondary melanotic sarcoma." (p334) Scarisbricj cites Sir Arthur Salisbury MacNalty's "The Death of Queen Catherine of Aragon", Nursing Mirror, 28 December 1962, but I have been unable to find a copy of MacNalty's article.
Antonia Fraser (The Six Wives of Henry VIII, p282) writes of how Sir Norman Moore, demonstrator of morbid anatomy at St Bartholomew's Hospital, and later President of the Royal Physicians, put Catherine's death down to melanotic sarcoma, the tumour on her heart being a secondary one and the chandler "having missed the primary growth". Moore discussed this in "The Death of Catherine of Aragon", The Athenaeum, 1885.
Although the chandler's findings meant that Catherine's loyal supporters could spread rumours of poison and murder, modern medical experts do not believe that the findings support this idea at all. Catherine died of natural causes, of cancer. Antonia Fraser writes of how it is "fanciful" and "romantic" to think that Catherine died of a broken heart, but "Nevertheless one notes that when Queen Catherine died, it was her heart that was most visibly affected. And that seems symbolic at least, if the connection is not medically sound." Whatever the actual cause of her death, Catherine was definitely nursing a broken heart.