Bernardo Soares is one of Fernando Pessoa's heteronyms, that is, a pen-name for one of the literary personalities he created to sign some of his works.
(My semi-heteronym Bernardo Soares, who in many ways resembles Álvaro de Campos, always appears when I'm sleepy or drowsy, so that my qualities of inhibition and rational thought are suspended; his prose is an endless reverie. He’s a semi-heteronym because his personality, although not my own, doesn’t differ from my own but is a mere mutilation of it. He’s me without my rationalism and emotions. His prose is the same as mine, except for certain formal restraint that reason imposes on my own writing, and his Portuguese is exactly the same – whereas Caeiro writes bad Portuguese, Campos writes it reasonably well but with mistakes such as "me myself" instead of "I myself", etc.., and Reis writes better than I, but with a purism I find excessive...). »
— Fernando Pessoa, "Letter to Adolfo Casais Monteiro", 13.01.1935, translated by Richard Zenith.<32>
(Taken from the Wikipedia entry "Fernando Pessoa")