Two years after he had been buried with pomp and ceremony, he suffered a Royalist posthumous execution - his head placed on a spike above Westminster Hall where it remained for 20 years. According to contemporary accounts, this plate was 'found in a leaden canister, lying on the breast of the corpse' by the man in charge of exhuming Cromwell's body - James Norfolke, Serjeant of the House of Commons.
Sotheby's will offer the 'relic' for sale on December 9. Estimated at £8000-12,000, it has been in the collection of the Harcourt family since the 19th century.
