From a literary and political point of view, the 17th century found Portugal in a state of decadence. Before Portugal lost its independence to Spain in 1580, Spanish influence had introduced the Inquisition and, with it, the censorship and suppression of books. In the 1550s the Jesuits had also gained control of higher education. A preoccupation with Classical Latin was already apparent, in the work of Camões and others, before the example of the Spanish poet Luis de Góngora y Argote was felt; but with the exhaustion of the national spirit that underlay Portugal’s political eclipse at the end of the 16th century, the influence of Góngora penetrated deeply. Its extent may be seen in the five volumes of Fénix renascida (1716–28; “Phoenix Reborn”), which anthologizes the poetry of the preceding century and shows the pervasiveness of Gongorism (gongorismo; see also culteranismo) in Portuguese poetry. This taste for the construction of literary enigmas, puzzles, labyrinths, and visual designs, all presented in an esoteric, Latinate style, led to cabalistic and occult exercises. Satire was used by those who wished to attack the dominant formalist style; the anonymous Arte de furtar (1652; “Art of Stealing”) unmasks social deviance in the time of John (João) IV, who was restored as king of a newly independent Portugal in 1640. Yet Spanish influence continued after Portugal regained its independence: use of Spanish was common, and the Portuguese court preferred Italian opera, French plays, and Spanish operettas, to the detriment of local drama and acting. The discovery of gold and diamonds in Brazil at Minas Gerais underwrote and prolonged the wealth of Baroque art in Portugal.

The foremost literary figure of the age was Francisco Manuel de Melo, whose works became classics of both Spanish and Portuguese literature. With Epanáforas de vária história portuguesa (1660; “Anaphoras of Diverse Portuguese History”), a series of historical episodes, and Apólogos dialogais (published posthumously in 1721), a collection of dialogues on literary and social topics, he strove to free himself from subservience to Spanish form and style. He was more successful in doing so in prose than in verse. Most lyricists of the period remained steeped in Gongorism. Epic poets continued to be active, but few of their productions were more than rhymed chronicles.

António Vieira—a Jesuit missionary and a diplomat who spent much of his life in Brazil and who was also preacher to the royal family in Lisbon and confessor to Queen Christina of Sweden in Rome—is known for his defense of indigenous peoples and slaves in Brazil and for the polished rhetorical flourishes and philosophical conceits in his volumes of Sermões (1679–1748; “Sermons”) and Cartas (1735–46; “Letters”). His impact on the written Portuguese language was second only to Camões. Luís de Sousa, a monastic chronicler, won fame as a stylist with Vida do arcebispo D. Frei Bartolomeu dos Mártires (1619; “Life of Archbishop D[ominican] Friar Bartolomeu dos Mártires”) and História de São Domingos (three parts, 1623, 1662, 1678; “History of St. Domingos”). His place in literary history was enhanced in the 19th century by Portuguese writer João Baptista de Almeida Garrett, who based a play on Sousa’s life.

The struggle for the social and intellectual emancipation of women appears in late Baroque literature produced in Portuguese convents, where some nuns rejected the restrictions placed on them. Violante do Céu produced an intellectualized poetry of concepts far beyond the norm of feminine sentimentality, while Maria do Céu wrote poetry in Castilian and Portuguese that expressed religious themes with a lyrical eroticism. In 1669 the publication in France of Lettres portugaises (“Portuguese Letters”; Eng. trans. The Love Letters of a Portuguese Nun) introduced a literary mystery that would enchant readers for centuries. These five short letters, purportedly translated into French from lost originals, were presented as love letters; they were later attributed to Mariana Alcoforado, a Portuguese nun who was abandoned at a convent in Beja by her lover, Noel Bouton de Chamilly, a French army officer stationed in Portugal in the 1660s. Although the letters are now thought to be the work of their supposed translator—the French lawyer and diplomat Gabriel-Joseph de Lavergne, vicomte de Guilleragues—and have been subsumed into French literature, they continue to be admired for their unsurpassable psychoanalysis of passion as well as for their perceived Peninsular consciousness. The Portuguese poet and statesman Teófilo Braga considered them the most beautiful works of the 17th century, and they were widely translated by European poets of note into the 20th century (including Rainer Maria Rilke in 1913). Scholars still debate the question of their authenticity and authorship, while poets, playwrights, and novelists dramatize their intense words of faith, doubt, and despair. The Portuguese nun of these letters is a literary paradigm as significant in European literature as that of Inês de Castro.