Oswald Spengler was a prominent German philosopher and historian who rose to fame with his controversial theory of cultural decline. He is often associated with the concept of a "civilization's end," a phrase which has become a synonym for his name. Spengler's work was highly influential in shaping modern social and political thought, and his ideas continue to be explored and debated today. Other synonyms for Spengler might include "historian," "philosopher," "cultural critic," and "author," as well as more specific terms related to his work, such as "pessimism," "historicist," and "anti-modernist." Regardless of the terminology used to describe him, Spengler's work remains an important touchstone in the study of civilization and cultural decline.