The literary concept of the heteronym refers to one or more imaginary character(s) created by a writer to write in different styles. Heteronyms differ from pen names in that the latter are just false names, while the former are characters that have their own supposed physiques, biographies, and writing styles.

Fernando António Nogueira Pessoa was a Portuguese poet, writer, literary critic, translator, publisher, and philosopher, described as one of the most significant literary figures of the 20th century and one of the greatest poets in the Portuguese language. He also wrote in and translated from English and French.