According to Charles's devotees, his execution was "judicial murder", as no king could be tried for treason - treason had always been defined as a crime against the king himself.
The Richard III Society rivals the Royal Martyr's following in fervour. Did Richard combine the crimes of regicide and infanticide, ordering the murder of his nephews Edward V and Richard of York, "the Princes in the Tower"? Even the ingenious defence by the Richard III Society struggles to outweigh centuries of condemnation. Mud sticks.
Britain may be the only country in which a long-ago royal murder - of or by a monarch - can still raise blood pressure, but other European countries have some admirable gruesomes and ghastlies. Take the 1355 murder of Ines de Castro, wife of the heir to the Portuguese throne, by order of her father-in-law the King (she was subversively Spanish). When her widower came to the throne, he had her skeleton exhumed, crowned and enthroned, and made his courtiers file past, kissing the bony hand.
However, for sheer horror, the career of Ivan "the Terrible" (more aptly "the Terrifying"), the 16th-century tsar of Russia, cannot be rivalled. In war, he took thousands of prisoners and himself supervised their killing: they were flayed, impaled, disembowelled, mauled by wild bears, buried alive, roasted over fires and frozen in icy rivers. But what Ivan liked best was killing with his own hands. A homicidal maniac.
A thousand years ago, royal murders were generally a family matter: between 993 and 1058, five Scottish kings were murdered by the cousins who succeeded them on the throne. Even in the 18th century, in Russia, Peter I had his son killed, Catherine II her husband.
Between 1898 and 1913 five of Europe's kings and a consort queen and empress were assassinated. This was the assassin's heyday, the culmination of a half-century of "propaganda by deed" by "revolutionists" in which the major success had been the assassination of the Russian Tsar Alexander II in 1881. Serbia's king and queen were the victims of a military coup in 1903, but it was the anarchist who was "the terror of kings". "Anarchist" was a catch-all term for every shade of extremism - nationalist, separatist, socialist, nihilist. It was taken up by the purple press, and the anarchist became the favourite villain of the tuppenny shockers on every bookstall.
Some monarchs became - or pretended to be - blase. "It's one of the risks of our profession," said King Umberto of Italy, survivor of several attacks; he was shot and killed in 1900. But no royal murder was as momentous as the assassination, in 1914 at Sarajevo, of the heir to the Austro-Hungarian Empire: it triggered - though it did not cause - the First World War.
Only last year, in May, a Basque terrorist plot against the life of Spain's King Juan Carlos was foiled: he was to have been killed at San Sebastian, while opening a new aquarium. As recently as 1996, a ground plan of Buckingham Palace was found in the effects of a dead IRA man. In fact, the IRA were not the instigators of the worst alarm, when six shots were fired at the Queen as she rode down the Mall in 1981. She could not know that they were blanks - but she had long since accepted "the risks of our profession".
Dulcie M. Ashdown is the author of 'Royal Murders: hatred, revenge and the seizing of power' (Sutton, pounds 18.99)Reuse content