On 30 January 1649, King Charles I of England took to the scaffold outside the Banqueting House in London’s Whitehall. He had requested two shirts to prevent himself from shivering from the cold, a reflex he thought could be mistaken for fear. He knelt in front of the crowd and placed his head on a block. Moments later, the axe fell.

Now, 371 years later, the pale blue vest worn by Charles during his execution is to go on display. “This undergarment would have been a good thing to wear in January because it is knitted silk, so it would have been a warm garment,” said Meriel Jeater, a curator at the Museum of London.

The silk vest is the star of an exhibition due to open in October that will look at public executions in London from 1196 to 1868. The latter date marks the last such execution – that of Michael Barrett, who was hanged for murder at Newgate prison after being found guilty of involvement in a bombing.

The vest is notable for its stains but whether they are the marks of a sticky end or the contents of a terrified king’s stomach remains unclear. “We have had tests done on them by forensics labs to try and work out if they are blood, but they were inconclusive,” said Jeater, noting that the stains fluoresce under UV light – as would be expected for sweat and vomit but not blood. However, experts suggested the passage of time may have changed the composition of the substances, she said.

Read more: The Guardian