Yeats incorporates his ideas on the gyre — a historical cycle of about 2,000 years. He first published this idea in his writing A Vision which predicted the expected anarchy that would be released around 2,000 years after the birth of Christ. The gyre suggests the image of a world spinning outward so that it cannot recall its own origin. These anxieties are closely tied to the traumas of a continent at war, and the rise of industrialism and militarism on a global scale.
This now seems quite prophetic given the events which have occurred since the year 2000AD.