Inconsequence of the Diet of 1792, by which the nobles had lost the rest of their privileges, there arose a conspiracy. The principal ringleaders were Ankarström, Count de Ribbing, Count de Horn, Baron d'Erenswaerd and Colonel Lilienhorn. Ankarström and Ribbing had private reasons for hatred against the king, besides the general grievances which embittered the aristocracy against the sovereign. Through the king's intervention Ankarström had lost a lawsuit which had deprived him of half his fortune. Count de Ribbing, as we have seen, owed a grudge against the king for a far more grievous loss than that of a lawsuit, namely, the loss of his lady-love. In the case of the other nobles the projected murder of Gustavus was simply an incident in the life of a clan. They decided to perpetrate the murder at a masked ball, which was to take place in the Opera House, on the night of 15 and 16 March 1792. On the night before, the king received an anonymous letter, warning him of the plot and telling him that he was to be assassinated on the following night.
"Ah yes," said Gustavus, "the very same thing was predicted twenty-two years ago to the Count de Haga; but he put no more faith in the prophecy than the King of Sweden does to-day;" and, shrugging his shoulders, he crumpled the note between his hands and threw it into the fireplace. Nevertheless, people averred that Gustavus went disguised on the night of the 14-15 to consult the famous sibyl Arfredson, who confirmed the French somnambulist's prediction and the warning contained in the anonymous letter, telling him he would be murdered before three days had gone by. Whether from actual courage or from incredulity, Gustavus would not change any of his previously arranged plans nor take any precaution: at eleven o'clock that night he went to the masked ball. Lots had been drawn the night before to settle which of the conspirators should kill the king, and Gustavus was so greatly detested by his nobles that each one was eager to have the dangerous honour of firing the fatal shot. The lot was drawn by Ankarström.
It is said that one of the conspirators offered to give him all the wealth he then possessed, as well as all that which he was to inherit at a future date, if he would change places with him; but Ankarström refused. When the time came, Ankarström suddenly bethought him that he might mistake one of the nobles for the king, as several of them were dressed in similar costumes. But the Count de Horn reassured him. "Fire boldly," said he, "at the one to whom I shall say, 'Good-day, handsome masquerader.' He will be the king."
At two in the morning Gustavus was strolling about, leaning on the arm of the Count d'Essen, whom he had married to de Ribbing's fiancée, when the Count de Horn approached him and said, "Good-day, handsome masquerader."
The next moment a dull report was heard, and Gustavus tottered, crying out—
"I am killed!"
Except those who were round about the king no one had perceived what had happened. The pistol was concealed in a muff; the report had been drowned amidst the buzz of conversation and the strains of the orchestra, and the smoke remained buried in the muff. But at the king's exclamation, and on seeing him fall back fainting in the arms of d'Essen, everyone ran up; in the commotion that followed it was quite easy for Ankarström to put himself at a distance from the king and even to leave the hall; but in his flight he dropped one of his pistols. The pistol was picked up, hot and still smoking. Next day every gun-seller in Stockholm was questioned, and one of them recognised the pistol as one he had sold to Ankarström. An hour later, Ankarström was arrested at his own house, and a special commission was appointed to try him. He confessed to, but gloried in, his crime. As to his accomplices, he declined under any conditions whatever to reveal their names. The trial dragged on slowly; it was hoped against hope that Ankarström would give away the conspirators; finally, on 29 April 1792, forty-four days after the murder, he was condemned. The sentence was that he was to be beaten with rods for three days, then beheaded. In spite of the length and the ignominy of the punishment, Ankarström remained firm to the very end. While being taken in the cart to his execution, he looked with perfect equanimity upon the thousands of spectators who thronged round the scaffold. When he mounted the scaffold he asked for a few minutes in which to make his peace with God. It was granted him. He knelt down, prayed and then gave himself up to the executioners. He was not quite thirty-three years of age.
Ribbing, who had been arrested at the same time as Ankarström, was but twenty-one: it was intended to condemn him to death like Ankarström, and the Duke of Sudermania, regent over the kingdom during the minority of Gustavus IV., was urging forward the trial, when a mystic, a disciple of Swedenborg, sought him out and told him that the master had appeared to him, and had declared that not only was Ribbing innocent, but that every hair which fell from his head would cost a day of the life of the Duke of Sudermania. The duke, a Swedenborgian himself, was terrified at this warning, and Ribbing, instead of sharing Ankarström's fate, was condemned to perpetual exile. And as less could not be done for the Count de Horn and for Lilienhorn than was done in the case of Ribbing, they both obtained the same favour. The confiscation of their property followed upon the sentence of exile. Fortunately, in the case of the Count de Ribbing, the confiscation of property could not be put into execution until after the death of his mother: she enjoyed the property in her own right, during her lifetime, and she was still quite young.
The count left for France, where the Revolution was then at its height, and he arrived in time to witness the events of 2 and 3 September and 21 January. His adoration for the queen made him loud in his denunciation of the events of those dreadful days. He was arrested and, although already a regicide, was on the point of being delivered up to the revolutionary tribunal as too sympathetic with royal misfortunes, when Chaumette set him free, gave him a passport and helped him to escape from Paris. The count then went to Switzerland; he was so young and so good-looking that he went by the name of "the beautiful regicide." He was introduced to Madame de Staël, who took him much into her confidence. The letters (some two or three hundred) which the Count de Ribbing received from Madame de Staël during the lifetime of the illustrious authoress of Corinne, proved that this friendship was not of a temporary nature. Madame de Staël was surrounded by a circle of friends, several of whom already knew the Count de Ribbing. This little court was half political and half literary; its chief purpose at that time was to rescue, hide and protect emigrants against the persecutions of the magistrates in the Swiss cantons whose hands were continually being forced by the demands of the Revolutionary Government of Paris.