A long and cloudless friendship connected Bely with his university friend A.S. Petrovsky. It arose at the very end of the 19th century and ended only with the death of Bely in 1934. And after that, Petrovsky remained faithful to the memory of his friend until the end of his days, continued to communicate with his widow and helped in every possible way in preserving the heritage, both literary and spiritual, of her husband. Many of Petrovsky’s letters to Bely have not reached us. However, those that have survived represent important evidence of the times and shed light on the long-term relationship between two bright, extraordinary personalities.