Given the task definition and input, reply with output. In this task you will be given a text passage from a trivia quiz. You should choose the category this question belongs to from these categories: History, Science, Social Science, Fine Arts, Literature. You can only choose one category, so if in doubt, please choose the closest match.

This poet described exchanging "polite meaningless words" with soldiers, and he notes that "whenever green is worn, a terrible beauty is born". The speaker of one of his poems believes not in "singing school but studying Monuments of its own magnificence," concluding that there is "no country for old men". This author of "Easter, 1916" invoked the "mere anarchy" soon to be "loosed upon the world" in a poem about a "rough beast" emerging from Spiritus Mundi, "slouch[ing] towards Bethlehem to be born". For 10 points, name this Anglo-Irish poet of "Sailing to Byzantium" and "The Second Coming".
Literature