Konstantin Karlovich Danzas was a schoolmate and friend of Alexander Pushkin at the Lyceum, as well as an officer. He was Pushkin’s second in his duel with d’Anthès. Danzas attended the School for Boys from Noble Families at Moscow University. At the request of Prince Dmitry Golitsyn and his sister Countess Sofia Stroganova, he was admitted to the Tsarskoye Selo Lyceum. There, he passed the exams with distinction, although he did not rank among the top students and was not known for exemplary behavior. At the Lyceum, he became close friends with Alexander Pushkin and Ivan Ivanovich Pushchin. Together with Delvig, he published a handwritten magazine called “Lyceum Sage” and wrote articles for it.

On the day of the duel, January 27 (February 8), 1837, Alexander Pushkin met his second, Danzas, at the corner of Nevsky Prospect and Moika Embankment, in the Wolf and Beranger Confectionery. The duel between Pushkin and Georges-Charles de Heeckeren d’Anthès, better known as d’Anthès, took place on the outskirts of Saint Petersburg, in the vicinity of the Chyornaya Rechka, a small river, in the woods near the Commandant’s Cottage. The duelists used pistols. The conditions of the duel were deadly and left no chance for both opponents to survive. According to the rules, they stood twenty paces apart, with a ten-pace barrier between them. It was permitted to shoot from any distance from the barrier. They used their overcoats, placing them on the ground to mark the barrier. Pushkin was mortally wounded. He died two days later.

Five days after the duel between Pushkin and d’Anthès, a military court was convened to hear the case. The punishment for d’Anthès was as follows,

Later, when recalling the final hours of Alexander Pushkin’s life, d’Anthès said,

In 1863, his account of the duel and the final days of Alexander Pushkin was published, transcribed by his friend and poet Alexander Nikolayevich Ammosov.