In ancient Greek, “Psyche” refers to the human soul and has its origin in a verb meaning “to breath.” Psyche is also the name of the Greek goddess of the soul. In Greek myth, Psyche is married to Eros, the god of love, a tale Keats writes about in his “Ode to Psyche.”
"Make not your rosary of yew-berries,..."See in text(Ode on Melancholy)
Keats alludes to the yew, a common European tree whose parts are toxic to humans. By referring to the rosary, a string of beads used in Catholic prayer, Keats expands the poem’s cultural scope beyond Greek mythology to include the Judeo-Christian tradition.
"By nightshade, ruby grape of Proserpine;..."See in text(Ode on Melancholy)
The speaker continues to request that the reader not turn to poison. Once again, Keats draws on a Greek reference, calling the poisonous nightshade flower the “ruby grape of Proserpine.” Proserpine is another name for Persephone, the Greek princess who winters with her husband, Hades, in the Underworld and who summers with her mother, Demeter, in the meadows and fields of the earth. The vibrant nightshade flower similarly represents the gateway between death and bounteous life.
"Wolf's-bane, tight-rooted, for its poisonous wine;..."See in text(Ode on Melancholy)
“Wolf’s-bane” is a colloquial name for the Aconitum genus of flowers, the majority of which are known for being incredibly poisonous. Like many of Keats’s references and images, Wolf’s-bane figures prominently in Greek myths: the witch Medea tried to poison Theseus with it, and the flower is said to have originated in the drooling mouth of Cerberus. The subtle allusion to Cerberus, the guard hound of the Underworld, is important. In the first stanza, the speaker urges melancholic souls not to drug themselves to death.
The River Lethe is one of the four rivers of the Greek underworld. It is the river of oblivion, whose waters souls must drink so as to forget their past lives. Keats’s speaker warns the addressee not to escape melancholy through opiates and numbness.