By Arthur Strain
BBC News website
It happened a century ago, but has all the ingredients of a modern detective thriller, theft, dishonour and rumours of sexual indiscretion.
Sir Arthur Vicars was blamed for the theft (Picture copyright of the Office of the Chief Herald of Ireland)
On 6 July 1907, the Irish 'crown jewels' were discovered to have been stolen from Dublin Castle.
The jewels were the insignia of the Illustrious Order of St Patrick, instituted in 1783 as the Irish equivalent of the Order of the Garter.
Normally kept in a bank vault, they had been moved in 1903 to Dublin Castle, the centre of British rule in pre-independence Ireland.
Their safe proved too big to fit into the strong room in the castle's Bedford Hall and was kept in the library, with Ulster King of Arms - a role begun in 1552 - Sir Arthur Vicars in charge of the keys.
Four days before a visit by King Edward VII and Queen Alexandra they were found to be missing, stolen from the safe - along with jewellery owned by Vicars' mother - by persons unknown.
The King had intended to invest Lord Castletown as a Knight of the Order, but angered by the theft he cancelled the ceremony.
Although under pressure, Vicars refused to resign and rumours were spread about his sexual orientation and wild parties at his office in the castle, with the objective of shaming him into leaving.
It did not work, and he refused to appear at a Viceregal Commission, demanding a public royal inquiry instead.
He accused his second in command, Francis Shackleton (brother of Ernest - the Antarctic explorer) of the wrongdoing.
However, Shackleton was exonerated by the commission, while Vicars was found culpable of failing to "exercise due vigilance or proper care" of the regalia.
Vicars felt as if he had been made a scapegoat and spent his remaining years as a recluse, in a 'big house' (ascendancy manor) in County Kerry.
On 14 April 1921, in the period between the War of Independence and the Civil War, an armed IRA contingent brought him out of Kilmorna Castle and shot him dead, before burning the building.
In his will he condemned both the Irish government and King Edward VII for making him a scapegoat and shielding 'the real culprit and thief', whom he specifically named as Francis Shackleton.
The tabard worn by Sir Arthur Vicars - copyright of the Office of the Chief Herald
Because of the explosive allegations, this will was closed to researchers until 1976.
Shackleton was convicted of fraud in 1913 - for misappropriating a widow's savings - and following his release from prison he assumed the surname Mellor and died in 1941 in Chichester.
The jewels were never recovered, and the knightly order has passed into history in the modern day Republic of Ireland.
Author of Dublin Castle at the Heart of Irish History, Denis McCarthy, said the episode had been whitewashed to purge the scandal, with all the papers relating to it destroyed.
"It was completely suppressed and the career of an innocent man was ruined," he said.
While Vicars and the scandal of the theft are firmly in the history books his heraldic role remains in the post of the Chief Herald of Ireland, currently Fergus Gillespie.
"It is the oldest Irish office and still granting arms, we get a lot of people in America with Irish ancestry contacting us about arms," he said.
Rumours have abounded over the fate of the jewels that they may still be hidden in Ireland, or somewhere in England, or alternatively are in the possession of a wealthy collector.
Susan Hood, author of Royal Roots - Republican Inheritance which focuses on the Irish Office of Arms, said the jewels may have been broken up.
"At the time with all the publicity they would have been hard to sell intact, but we'll never know for sure," she said.