During his lifetime, Fernando Pessoa only published four books. Just one of these was written in Portuguese and two of them are small books of poems:
English Poems, I-II
English Poems, III
All of these books were published in his own name, despite the fact that Pessoa had already created the famous heteronyms that were to mark his literary production: Alberto Caeiro, Álvaro de Campos and Ricardo Reis, whom he presented in the magazines Orpheu (1915) and Athena (1924 and 1925).
Orthonym was the term that he used to refer to the authorship of the poems, texts and other works published and signed by Fernando Pessoa. This was how he himself explained the situation in the bibliographical table that was published in Issue No. 17 of the magazine Presença, in 1928.
What Fernando Pessoa writes belongs to categories of work which we could call orthonyms and heteronyms. It cannot be said that they are anonymous or pseudonymous because they really aren't. The pseudonymous work is by the author in his own person, except he signs it with another name; the heteronymic work is by the author outside his own person, it is the work of an individual completely fabricated by him, as if they were the words of any character in any of his dramas
Besides these three heteronyms, Fernando Pessoa also recognised a semi-heteronym, Bernardo Soares, who, although he did not have a voice that was distinct from his own, always appeared whenever he was «tired or sleepy, so that his qualities of reasoning and inhibition were always a little suspended».