De orbis terrae concordia is among the earliest printed blueprints for a universal religion—a reasoned program that reads the Qurʾān end-to-end and extends peaceful concord across law, language, and the newly encountered Americas. MOUSEION CURATOR NOTE: “A Renaissance attempt at world-making: Postel fuses philology, law, and theology into a single instrument for peace, printed by the very shop that had just set the Qurʾān in type. The result is a founding artifact of religious comparatism—ambitious, disruptive, and timely still.” THE VOLUME: Guillaume Postel. De orbis terrae concordia libri quatuor. [Basel: Johann Oporinus], 1544. Small folio. First complete edition—Paris had issued only Book I in 1543. Collation as usual: [4] ff., 447 pp. (misnumbered 427), final leaf blank; signatures [α] a–2n 2o. Contemporary panelled blind-stamped pigskin with two sets of initials on the upper cover (“P-T-B” and “I-M-M”), rebacked in calf; scattered early marginalia. References: VD16 P 4481; Adams P 2020. DESCRIPTION: Conceived in the wake of interconfessional wars and new geographies, this first complete edition Concordia gathers four books into a single architecture of reconciliation: Book I sets out Christianity’s doctrines “rationibus philosophicis,” staking a rational foundation for faith. Book II narrates Muḥammad’s life and examines the Qurʾān from end to end for comparison and critique—unthinkable without the philological resources Postel helped naturalize in France. Book III identifies what is common to the whole world “in human as well as divine law,” the bedrock for civil order across traditions. Book IV asks how, sine seditione, peoples might be won to truth—through policy, pedagogy, and persuasion. Postel’s project culminates in a workable politics of peace: in Books III–IV he identifies what all peoples share in human as well as divine law—and then prescribes the non-seditious arts by which they may be drawn toward truth through education, policy, and reasoned appeal. Concord, in his scheme, is to be achieved by persuasion rather than coercion. As recent scholarship emphasizes, Postel’s universalism is not mere irenicism; it welds linguistic and legal unities to its theology. In Concordia he valorizes Hebrew as the first and universal language—a philological myth pressed into service for political-religious unity—while aligning his program with the ideal of a universal monarchy (themes he would develop further). The Basel imprint matters. Oporinus, having issued Bibliander’s Latin Qurʾān in 1543 (some copies with Luther’s prefatory warning to study Islam for refutation), positioned Basel as Europe’s safest press for high-risk comparative religion; Concordia is its logical sequel in scope and ambition. For private or institutional libraries building early tolerance / interfaith narratives, or mapping Europe’s first scholarly contact with Islam, Concordia is foundational and materially eloquent. Finally, the book’s global compass reaches beyond the Mediterranean and Levant to the newly encountered Americas: in the later leaves (pp. 350–353) Postel turns explicitly to the peoples of the New World, urging their instruction and incorporation into a common Christian civil order—evidence that his envisioned orbis is geographic and juridical no less than doctrinal. SELECTED QUOTATIONS: Postel to the reader (title and prefatory leaf): this book is “replete with manifold learning and piety”—nothing more useful could appear “in these troubled times.” Marion L. Kuntz : “Postel was among the first to proclaim the need for a universal religion and a universal state.” G. J. Toomer (Oxford): Postel “deserves, if anyone, to be called the father of Arabic studies in France.” Ewa Łukaszyk: Postel was a “theoretician of the universal monarchy,” obsessed with unity at every level of human life. PROVENANCE: Contemporary blind-stamped pigskin, upper cover with the initials “P-T-B” and “I-M-M”; the same pairs appear in ink at the foot of the title, some early marginalia present. CONDITION REPORT: Title with marginal repairs; [α]2–3 upper corner torn (some text supplied in manuscript); a1–4 small worming; b2 short tear without loss; 2D6 tiny hole affecting a few letters; minor inner-margin worm trace at end; final leaf laid down; spotting and water-stained; rebacked; front cover joint cracked but holding. Binding stained and worn. A complete, serviceable copy in contemporaneous dress—honest, legible, and collectible. ADDITIONAL INFORMATION: A first complete edition that makes early comparative religion legible in print; a Basel Oporinus book placed directly after the first printed Latin Qurʾān; a programmatic theology that treats Islam textually and argues for peaceable persuasion; and a contemporary binding with distinctive initials and early reader’s marks—plus the book’s own declared utility “in these troubled times.” Context note (Cusa to Postel). Fifteenth-century precursors such as Nicholas of Cusa’s De pace fidei (1453) imagine peace among religions; Postel is among the first to operationalize such peace in a printed, four-part program addressing doctrine, law, and policy, and to do so with sustained, textual engagement with the Qurʾān.