Simon is a children's historical novel written by Rosemary Sutcliff

Rosemary Sutcliff

Rosemary Sutcliff CBE was a British novelist, and writer for children, best known as a writer of historical fiction and children's literature. Although she was primarily a children's author, the quality and depth of her writing also appeals to adults; Sutcliff herself once commented that she wrote...

, first published in 1953. It is set during the English Civil War

English Civil War

The English Civil War was a series of armed conflicts and political machinations between Parliamentarians and Royalists...

, and shows the effect of the conflict on two friends, who find themselves on opposite sides. It is her fifth novel, acknowledged to be the first in which she displayed the mastery of subject and style for which she is known.
The story begins on the eve of the English Civil War in 1642.