Oswald Spengler

Oswald Spengler (29 May 1880-8 May 1936) was a German philosopher and schoolteacher. He was mostly active in the areas of the philosophy of history, and cultural history. He also had antidemocratic ideas. He was part of a group of people called Konservative Revolution. His main work, The Decline of the West (original: Der Untergang des Abendlandes), he is against telling the story of humanity as a linear story of advances and successes. Instead, he says that history is cyclic: new cultures arise, they are successful, and they vanish again. He also says that the different cultures are well-defined, and clearly distinguishable. One such culture usually has a "lifetime" of about 1.000 years. Even in the title of his work, he says that the culture of the West (he used the term Abendland, occident, in English), is in decline. 
According to his contemporaries, Spengler correctly predicted some historical developments. He also influenced a few historians, such as Franz Borkenau and Arnold J. Toynbee. 
Spengler also published a number of minor works. As he saw that the Weimar Republic didn't work, he hoped that there would be a dictator thar would be strong enough to master the political challenges, in internal and foreign policy. Spengler talked about an era of wars of annihilation (such as the First World War). Spengler was also against National Socialism. He thought that antisemitism (as propagated by the Nazis) was too simple to be a solution for the problems of the time. He also thought that Benito Mussolini was better at what he did than Adolf Hitler.
Spengler died of a heart attack in his apartment in Munich, on May 8, 1936. 
The Nazis were ambivalent as to Spengler: Some saw him as one of the philosophical forefathers, others though that his ideas were too antiquated to be useful. As a philosopher, Alfred Baeumler was much closer to Nazi ideologies.