"One of the striking things about 'Western civilization' is that as an idea it is not particularly old."

“It came to the fore during World War I, when the fight against Germany and its allies — the Ottoman and Austro-Hungarian empires — was conceived by Anglophone liberals as a war of Western civilization against Eastern despotism. John Maynard Keynes, a cosmopolitan liberal, was convinced there was a civilizational gulf even between Germans and Anglo-Saxons, while the Russians, though allied with the West, were well beyond the pale of Western modernity. In the wake of World War I, courses on 'Western Civilization' began to be taught at elite American universities. By the onset of the Cold War, the term 'Free World' supplanted 'the West' because American power demanded a more globally inclusive banner that could rally South Vietnamese, Indonesians and others in the war on Communist 'slave societies.' After the Cold War, however, conservative American thinkers, such as Samuel Huntington, revived the idea of 'Western civilization' as a way of dramatizing how a set of values was now under siege from new threats: migrants, terrorists and moral relativists."

From "Vladimir Putin Has Revived ‘The West.’ Is That a Good Thing?" by Thomas Meaney, who does not think it's a good thing.