How does the setting relate to the events of the novel?

Certainly there are parts of this novel that are integral to the 1900's. There is Dunstan's "religious" experience in world war one, the stock market crash, and the Spanish flu. There are also the sensibilities of this era that come through. There are the travelling carnivals, which bring a sense of the mythical to Dunstan's life that he so craves. These are a few ideas for you.