Something that's influenced by or related to the English poet John Donne can be called Donnian.
If you study John Donne's work, you can call yourself a Donnian, or a scholar of his poetry. Also, poems by other writers might remind you of Donne's, and you could describe them as Donnian too. A Donnian piece of writing might incorporate themes of love, and of lovers creating an entire world between the two of them, as in Donne's poem "The Sun Rising," in which the sun is instructed to shine only on the narrator and his love.