Nikolai Gumilyov was outraged by the thought that his passionate romantic correspondence might in fact have been with a mocking Maximilian Voloshin (however, Dmitrieva claimed that all the letters to Gumilev were written by her, and that she had indeed been in love, but had recognized the romance would end the moment Gumilyov saw her).

On November 19, 1909, in the studio of artist Ivan Bilibin, Gumilev slapped Voloshin across the face, which by the customs of the time made a duel inevitable. The duel took place on November 22 on the banks of Chernaya river, the site of the fatal duel between Alexander Pushkin and Georges d'Anthès). Voloshin's second was Aleksei Nikolaevich Tolstoi, Gumilev's second was Ioganess von Gunter.

The peace-loving Voloshin did not want to kill Gumilev, and wanted even less to be killed himself, so he planned a psychological diversion to defuse the situation. While walking to the place of the duel he lost one of his pair of galoshes in the mud, and claimed that he could not shoot until the missing boot was found. Both seconds started to look for it, and within half an hour Gumilev joined the search. When eventually the boot was found, the duel had become psychologically impossible, and both participants agreed on a truce. Gumilev was still angry with Voloshin and broke all contacts with him, until suddenly in 1921 (a few months before his death) he visited Voloshin and restored their friendship.

from wikipedia.org