While his family remained in South Africa, Pessoa returned to Lisbon in 1905 to study diplomacy. After a period of illness, and two years of poor results, a student strike against the dictatorship of Prime Minister João Franco put an end to his formal studies. Pessoa became an autodidact, a devoted reader who spent a lot of time at the library. In August 1907, he started working as a practitioner at R.G. Dun & Company, an American mercantile information agency (currently D&B, Dun & Bradstreet). His grandmother died in September and left him a small inheritance, which he spent on setting up his own publishing house, the "Empreza Ibis". The venture was not successful and closed down in 1910, but the name ibis, the sacred bird of Ancient Egypt and inventor of the alphabet in Greek mythology, would remain an important symbolic reference for him.
In his early years, Pessoa was influenced by major English classic poets such as Shakespeare, Milton and Pope, or romantics like Shelley, Byron, Keats, Wordsworth, Coleridge and Tennyson. After his return to Lisbon in 1905, Pessoa was influenced by French symbolists and decadentists as Charles Baudelaire, Maurice Rollinat, Stéphane Mallarmé; mainly by Portuguese poets as Antero de Quental, Gomes Leal, Cesário Verde, António Nobre, Camilo Pessanha or Teixeira de Pascoaes. Later on, he was also influenced by modernists as W. B. Yeats, James Joyce, Ezra Pound and T. S. Eliot, among many other writers.