Any attempt to demonstrate the exegetical nature of Camões's project must inevitably involve some close readings of specific textual passages—readings that are unlikely to be fully satisfying without considerably more preparation. One obvious place to begin is with the poem upon which Camões's own poem is most clearly dependent: the psalm Super flumina. Like many great poets, Camões was first a great reader. Contemporary literary criticism has adopted a grandiose neologism—intertextuality—to denote the phenomenon of an author's commerce with anterior literary tradition. In the old Latin literary vocabulary the term most frequently used was imitatio, a word of far greater denotative range than its modern English reflex. As a poet of tradition, Luís de Camões is a conspicuously “imitative” or “intertextual” writer. The opening lines of Sôbolos rios engage with at least two very famous earlier texts, the Consolatio philosophiae of Boethius and the Commedia of Dante Alighieri. Among the great poets of classical Latinity with whom Camões has commerce, Virgil, Horace, and Ovid are conspicuous. His development of the theme of Orpheus is built upon texts in Virgil and Ovid as already engaged by Boethius. Petrarch is in his poem, which also includes an actual citation, in Castilian, of his much-admired Juan Boscán.

In a subsequent chapter I shall attempt a more comprehensive demonstration of his “art of intertextuality” in Sôbolos rios, as it involves a rich tradition of anterior secular poetry. But there are more pressing preparatory tasks, the first of which is to consider some implications of his most fundamental “intertextual” engagement—with what was universally in Camões's age called the sacred text (meaning the Bible), and indeed with its most literarily privileged pages. The Book of Psalms is a unique bridge or conduit, channeling the poetic life of ancient Israel into the liturgical life of the medieval Church. The Psalms kept ever vivid in the Church's memory a poetic history of God's marvelous dealings with his people of old, and offered prophetic promises of interventions yet greater to come.

For this reason, it would be nearly impossible to exaggerate the importance of the Psalms in the creation of the medieval literary imagination. For the better part of a millennium professional ascetics had a near monopoly on the skills of literacy and the arts of their cultural transmission.