Here's one possible answer:

Dante Gabriel Rossetti completed the first version of “The Blessed Damozel” in 1847 and published it in the February 1850 issue of The Germ, a journal of the pre-Raphaelite movement in painting and literature. He conceived the idea for the poem (and later a painting with the same title and subject) after reading Edgar Allan Poe's “The Raven,” about a man who mourns the death of his beloved Lenore, and after reviewing Dante Allighieri's Divine Comedy, in which the author's first love, Beatrice, escorts him from Purgatory to Heaven during his imaginary journey through the realms of the afterlife. The damozel of Rossetti's poem is thus a kind of composite of Lenore and Beatrice who pines for her earthbound lover. Rossetti revised and republished the poem in 1856 in The Oxford and Cambridge Magazine and in 1870 in Poems by D.G. Rossetti. As to the influence of Poe, Rossetti told his biographer, T. Hall Caine, that he wrote "The Blessed Damozel" as a sequel to "The Raven," saying, "I saw that Poe had done the utmost that it was possible to do with the grief of a lover on earth, and so [I] determined to reverse the conditions, and give utterance to the yearning of the loved one in heaven. (see the link below)

Other possible sources that I found in an quick internet search were less precise. Some suggest that Keats' poetry provided the inspiration.