On the feast of the Epiphany, the Tsar, his family and the diplomatic corps traditionally watched the Great Blessing of the Waters on the Frozen River Neva by the Winter Palace in St Petersburg.
Since the time of Peter the Great the ceremony was accompanied by a regimental gun salute - provided on January 6, 1905, by the first battery of the Guard's Horse Artillery. As the salute was fired, it became clear - as grapeshot began to ricochet against the palace stonework - that 'number one' gun was live.
Against a backdrop of revolutionary discontent, the Tsar viewed the incident as an attempt on his life.
One piece of shot had come close to hitting him and was retrieved from his feet by Grand Duke Nicholas Nicholaievitch. He took it to Fabergé and had it mounted in gold and white chalcedony as a seal by chief workmaster, Henrik Wigström.
Engraved in Cyrillic Recalling the salute of the 6th January 1905, it was presented to his Majesty as a souvenir of the occasion.
The historic seal, that descended in the family of the Russian general Prince Michael Cantacuzène (1875-1955), will be a highlight of Wartski's stand at TEFAF Maastricht, priced at £500,000.
Although a special commission concluded the Epiphany salute was nothing more than a mistake, the incident was, inadvertently a catalyst for the Revolution of 1905. Just three days later, when protestors marched on the Winter Palace imploring reform, jittery Palace troops chose to open fire on the peaceful crowd. Hundreds died.
• TEFAF Maastricht runs from March 15-24. See pages 22-28.