The basic simple roots of Expressionism come from Vincent Van Gogh , Edvard Munch , and James Ensor . They were the founding fathers of Expressionism and got the ball rolling. This is why so many people confuse impressionism and expressionism and in all reality, they are the exact opposites. It painted a scene that occured in Hiroshima when the A-bomb was dropped and totally sounded great when the text was put with the music. Without the text of the music however, the piece sounds awful and that is where expressionism comes in.
Expressionism is expression, and simply expression.
A piece that I really drew to was The War Requiem by Benjamin Britten . The Master of the Queen's Music, Sir Arthur Bliss, not long after this and in my hearing, described Britten as England's greatest composer. Britten was so highly esteemed by his colleagues after this came out in 1961, and this was rightly so because of the music he had written was so good. I found it very odd, yet fascinating, however, that despite all of this new music and all of this new stuff that Britten had written, the text was in the ancient Latin and it was taken out of the old liturgy of the Catholic Church. I find this very bizarre, yet very neat.