"...the better a reader understands the political, religious, and literary assumptions of a writer, the easier it will be to recognize the allegorical significance of his or her work."

From:

Literature
Reading, Reacting, Writing

Laurie G. Kirszner and Stephen R. Mandell:

"Naturally, the better a reader understands the political, religious, and literary assumptions of a writer, the easier it will be to recognize the allegorical significance of his or her work. John Bunyan's The Pilgrim's Progress, for example, is a famous seventeenth-century allegory based on the Christian doctrine of salvation. In order to appreciate the complexity of Bunyan's work, readers would have to familiarize themselves with this doctrine."