Boxen was the childhood imaginary land shared by C.S. Lewis and his brother Warren.
Lewis and Warren created Boxen during their childhood in Belfast. The imaginary world combined two earlier inventions: Box, a land of talking animals, and India, a land created by Warren. Their stories, maps, and drawings formed an extensive private mythology long before Lewis became a published author.
The brothers’ interest in invented worlds was encouraged by their reading and by their habit of writing and illustrating stories. Lewis later identified this early imaginative activity as part of the background to his literary development, although Boxen is separate from Narnia.
Boxen should not be confused with Lewis’s mature fantasy setting. Narnia was created for The Lion, the Witch and the Wardrobe and has its own cosmology, history, and characters. Some broad interests overlap, especially talking animals and invented societies, but the two worlds are not the same fictional universe.