As Yeats received the Nobel Prize in 1923, he was in the extremity of honor but he was feeling his weakening physical power. He gave up Maud Gonne and married George Hyde Ridge, a wise woman, to find a comfort at his home. His later poems are a record of his meditation and wisdom of life, and in those poems the image of Gyre is very important. He thought the progress of one civilization lasted for only 2,000 years and that is expressed through the image of the Gyre. The period of the early 20th century was a time of a kind of anarchy and a situation of desperation. He thought it was a turning point to a new terrible civilization. His poem "The Second Coming" is very meaningful in that view point and so is "Leda and Swan". Then his self consciousness of his old age and wisdom is well expressed in his "Tower" and Byzantium poems. But his self consciousness is not ended to a desperation but overcome to an immortal wisdom and art. In "Sailing to Byzantium" he sang the immortal art with a exquisite artisan spirit. And he particularly sang the world of soul and art in this poem. This is succeeded in "Byzantium". It is almost a song of spirit. As he grew old, Yeats concentrated his energy on the problem of spirit. As T. S. Eliot escaped to Hinduist meditation to overcome the limit of his early poems, Yeats made his particular view of history and civilization to enhance his poetry. If he had not opened his new poetic world in his later life, he could not have become that great poet we love so much.