Beginning in the sixth century C.E. and continuing for more than a thousand years, an extraordinary poetic practice was the trademark of a major literary movement in South Asia. Authors invented a special language to depict both the apparent and hidden sides of disguised or dual characters, and then used it to narrate India's major epics, the Ramayana and the Mahabharata, simultaneously.

Originally produced in Sanskrit, these dual narratives eventually worked their way into regional languages, especially Telugu and Tamil, and other artistic media, such as sculpture. Scholars...