Fernando Pessoa
Pessoa wrote poems and other things as if they were written by persons who are not himself in any way. Each person had his own life story, physical qualities, relationship to the others, poetic voice, and point of view.  These are called "heteronyms." Pessoa invented at least 72 of these other persons. His three main poets, for example, are described like this: "Alberto Caeiro, a rural, uneducated poet of great ideas who wrote in free verse; Ricardo Reis, a physician who composed formal odes influenced by Horace; and Álvaro de Campos, an adventurous London-based naval engineer influenced by poet Walt Whitman and the Italian Futurists."