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 (or pseudonyms, from the Greek words for "false" and "name") in that the latter are just false names, while the former are characters that have their own supposed physiques, biographies, and writing styles.[1]
Heteronyms were named and developed by the Portuguese writer and poet Fernando Pessoa in the early 20th century, but they were thoroughly explored by the Danish philosopher Kierkegaard in the 19th century and have also been used by other writers.