The paper considers one of the possible sources of Osip Mandelstam’s poem “Where was he taken from? Who? Who died?” included in the lyrical cycle in honor of Andrei Bely. The lack of the autograph and final version of the author complicates interpretation and poses some questions to be solved by researchers. One of them is the question of possible literary sources of the text. Traditionally, some memories of Pushkin’s and Gogol’s funeral and the episode of “Journey to Erzurum” by Pushkin related to the Griboyedov’s fortune were regarded as possible pretexts and parallels to Mandelstam’s poem. The research conducted allows extending this list and introducing a poem by Piotr Vyazemsky “So-and-so died. Well? He there lived and died” from the lyrical cycle “The Melancholy with glimpses.” The poems of Vyazemsky and Mandelstam are written in the same verse and are close in lexical, syntactic and compositional aspects. Of particular interest is the verbal formula “departed for Rostov,” quoted by Vyazemsky in the epigraph, and the text of the poem. This formula refers to death in obscurity and goes back to cholera in Moscow in 1771 in the poem of Ivan Dmitriev. Mandelstam’s general interest to the Russian poetry of Pushkin’s era, particularly to Vyazemsky and Ivan Dmitriev, and to the plot of the “Feast during the plague” suggests that Mandelstam consciously projects the situation of Vyazemsky approaching to Dmitriev on his own appeal to Andrei Bely.