"This shot split Russian history in two. It was destined to open a new era with a tall, fair-haired, sullen and silent young man with a long horse-like face, a low voice, and a heavy gaze. The bullet he prepared for the emperor did not reach its target; but it was this bullet that brought death to Sipyagin and Stolypin, Volodarsky and Uritsky, Nicholas II, Mirbach, Kirov, countless victims of the Civil War and Stalin's repressions." — Andrzej Ikonnikov-Galitsky.

Karakozov was the son, as stated in his case file, of an insignificant landowner from the Saratov province, who lost almost everything as a result of the peasant reform. In 1861, for participating in riots, young Karakozov was expelled from Kazan University (symbolically, Lenin-Ulyanov was later expelled from the same university), but two years later he was able to be reinstated, then transferred to Moscow University, from which he was also expelled in 1865 for inability to pay tuition. Karakozov often fell into depression, which he treated with opium. However, at the trial, Karakozov was declared sane and fully aware of his actions.

Soon Karakozov found like-minded people who approved of the ideas of revolutionary assassinations in general and regicide in particular. This was a circle of his cousin Ishutin, with the pretentious name "Hell." They believed that killing the tsar would lead to unrest in the country and a general revolution. Some members of the circle doubted the correctness of the chosen tactic and went to St. Petersburg to persuade Karakozov to return to Moscow. They found their comrade on the embankment near the Winter Palace, dressed in peasant clothes, looking out for the tsar. Karakozov was taken to a hotel and made to promise to return. However, he did not stay long in Moscow and again went to the capital. He knew that the emperor liked to walk in the Summer Garden and at the end of the walk always greeted the crowd of subjects. It was only necessary to get closer and shoot.

On April 4, 1866, Karakozov was slightly late, and by the time he arrived, a fairly large crowd had already gathered near the Summer Garden. Making his way through it, Karakozov mercilessly kicked the hat maker Osip Komissarov, who, offended, decided to catch up with the offender and get even. Around four in the afternoon, Alexander II finished his usual walk in the Summer Garden and came out onto the Nevsky Embankment. At that time, there was still no security detail with the emperor; a lone policeman was walking on the sidewalk outside the gates, and a gendarme corporal was waiting near the carriage.

Karakozov pushed forward, and at the appearance of the emperor, pulled a revolver from his pocket and prepared to shoot. But the arriving Komissarov struck him under the arm, so the bullet went upwards, and in the next moment the terrorist was subdued. Alexander II decided to exchange a few words with him, initially thinking he was Polish (just recently another Polish uprising had been suppressed). However, Karakozov declared himself Russian and said: "Your Majesty, you have offended the peasants!"

The former peasant from the Kostroma province, by the emperor's will, became a hereditary nobleman Komissarov-Kostromsky. The St. Petersburg nobility organized a subscription, collected more than 30,000 rubles, and bought him a house in the capital. For several weeks he was enthusiastically welcomed everywhere. Newspapers enthusiastically described the ovation Komissarov and his wife received at the theater, where the audience insisted they come out on stage. However, the following year there was another assassination attempt, and the hero of the first was forgotten. On September 3 (15), 1866, Dmitry Karakozov was hanged at Smolensk Field on Vasilievsky Island. Among the crowd wishing to see the criminal was the artist Ilya Repin. The execution made a heavy impression on him. After the event, he made a pencil sketch depicting an emaciated, powerless man. At the site of the assassination attempt, a marble chapel-monument was erected with the inscription "Touch not My Anointed One," which was demolished in 1930.

Sources:

https://i-fakt.ru

https://www.bbc.com/russian/features-37186194

https://sputnikipogrom.com/history/52094/the-emperor-hunt/