There is some debate about when the period of modernism began, however, popular opinion is that came into prominence at the start of the 20th century. Going off this assumption, the First World War was the most significant war to precede the period of modernism, or least be prominent at that time.
Modernism can be traced back to around 1850, and continued until around 1965. But, it really flourished between 1900 - 1930, hence the view point that it largely followed World War I, which started in 1914.
It was a social response to the politics of the era, and World War I only further spurred the movement. The move to modernist thought was a significant shift from the Victorian ideals which came before it.
Modernism advocated a move from traditional belief systems, most namely the move away from religious practices. The scale and destruction of WWI was heavily criticized by artist who are considered part of the modernist movement.
Hannah Hoch is a great example of a modernist artist, below is a piece of her work which represents the destructive and chaotic nature of war.
Her work can be more specifically categorised into the dada movement, which commonly termed an anti-war movement of the modernist era.
Modernism also continues over the periods of time which saw World War II, and the Cold War, and as such it could be seen to follow these wars, too.
