William Butler Yeats began his poetic career preoccupied by lofty themes of transcendentalism. As he aged, his lyrical mastery of memorable phrase-making and striking ability to conceive captivating metaphors ensured his place as the best Irish poet of his generation. In 1923, his reputation reached lasting international acclaim when he won the Nobel Prize. Acting as a monumental bridge between the romantic literature of the 19th century and the disillusioned poetry of modernism, Yeats inspired an enormous number of brilliant future poets including, TS Eliot, Ezra Pound, Allen Ginsberg and WH Auden, among others. Fascinated by esoteric studies and mystical phenomena, Yeats spent much of his intellectual life investigating strange occurrences in nature and supposed cases of psychic events. He subscribed to theosophical notions of existence, time and death, and symbolically drew from those arcane assertions to adorn his pioneering poetry. This week’s poem is one of his best known.