Copernican Letters by Galileo Galilei Facsimile Edition

Between 1612 and 1615, Galileo Galilei composed a series of texts now known as the Copernican Letters, written at the height of mounting tensions between emerging scientific inquiry and ecclesiastical authority. These letters—addressed to figures such as Benedetto Castelli and the Grand Duchess Christina of Lorraine—transcend private correspondence.

Circulated in manuscript form, they functioned as carefully argued treatises defending the compatibility of heliocentrism with Sacred Scripture, even as critics denounced the new cosmology as theologically suspect.

Historical Context and Polemic

The immediate catalyst was a sermon delivered in 1614 by the Dominican Tommaso Caccini and earlier criticisms by Niccolò Lorini, who claimed that Copernican theory contradicted biblical passages such as Joshua 10:13, where the Sun is said to “stand still.”

Galileo’s Letter to Castelli (1613) and expanded Letter to Christina of Lorraine (1615) respond directly to such charges. Written amid the intellectual climate that would culminate in the 1616 condemnation of Copernicanism, these texts mark a decisive moment in the Galileo affair.

Exegesis and Natural Philosophy

Galileo’s argument rests on a nuanced hermeneutic. Scripture, he contends, is infallible in matters of faith but accommodates itself to common understanding in matters of nature. Nature, by contrast, operates according to immutable laws accessible through “sensate experience and necessary demonstrations.”

The famous dictum—“Scripture teaches us how to go to heaven, not how the heavens go”—encapsulates his claim for the autonomy of scientific investigation. Notably, Galileo interprets the miracle of Joshua as more compatible with heliocentrism than with Ptolemaic cosmology, turning literalism against itself.

Manuscript Circulation and Intellectual Legacy

Though never formally published in Galileo’s lifetime, the letters circulated widely in manuscript, provoking admiration and alarm alike. Revised versions reveal Galileo’s strategic efforts to clarify orthodoxy while preserving intellectual independence. In tone both assertive and devout, the Copernican Letters illuminate a pivotal transformation in early modern thought: the gradual disentangling of theological authority from empirical science, a process that would reshape European intellectual history.

Manuscript Transmission and Preservation

The surviving autograph manuscripts of the Copernican Letters are preserved today in the Biblioteca Nazionale Centrale di Firenze, within the distinguished Fondo Galileiano (MS Gal. 87). This Florentine collection safeguards Galileo’s own hand in the Letter to Benedetto Castelli (21 December 1613) and in the draft of the more expansive Letter to Christina of Lorraine (1615), documents that reveal the evolving texture of his argument through revisions and refinements.

A separate and historically consequential copy of the Letter to Castelli—the version transmitted to Rome in 1615 by the Dominican Niccolò Lorini—survives in the Archivio Apostolico Vaticano, among the papers of the former Congregation of the Holy Office (Processi di Galileo, 1616 dossier).