The sea is calm tonight, and Arnold stands at a window looking out at the moonlit strait, listening to the waves draw back with their melancholy roar. In thirty-seven lines, he moves from sensory beauty to existential crisis: the Sea of Faith is retreating, leaving only naked shingles and a darkling plain. The poem was written during his honeymoon, which makes its plea to his beloved all the more urgent. Victorian England heard in it their own religious doubt given musical form. The final image of ignorant armies clashing by night has never stopped being relevant. It is one of the essential poems of modernity's loneliness.