Dialogo [...] dove ne i congressi di quattro giornate si discorre sopra i due massimi sistemi del mondo Tolemaico, e Copernicano; proponendo indeterminatamente le ragioni filosofiche, e naturali tanto per luna, quanto per laltra parte

Autore GALILEI, Galileo (1564-1642).
Tipografo Giovanni Battista Landini
Dati tipografici Firenze, 
Prezzo 36000.00
Dialogo sopra i due massimi sistemi del mondo

4to (219x161 mm). [8], 458, [34] pp. Collation: [π]4A-Z8 Aa-Ee8 Ff6 Gg-Kk4.Leaf Kk4 is a blank. Printer's device on title page and numerous woodcut diagrams and illustrations in text. Lacking the engraved frontispiece by Stefano della Bella showing Aristotle talking to Ptolemy and Copernicus. As in many copies, there is a printed correction slip pasted to the margin of p. 92; on p. 192 the letter H of the diagram is supplied by hand, as usual. Contemporary vellum, later lettering piece on spine. On the front pastedown is the manuscript pressmark “G10” written in red ink; on recto of the following flyleaf is a manuscript note (an ownership inscription?) “E. Nuqis.”. On title page the contemporary ownership inscription “Ex lib Jo Orat Mannajoni”, probably a member of the Mannaioni family from Montaione, Florence. Brown stain to the lower blank margin of about fifty leaves, slightly browned throughout, some gatherings more significantly browned. A very good, genuine copy with good margins, housed in its strictly contemporary binding.

FIRST EDITION of the ‘Dialogue on the Two Chief Systems of the World', universally considered to be Galileo's scientific and literary masterpiece.

To support the new Copernican conception of the universe without attracting the suspicions of the Inquisition, the author arranged the text as a four-day dialogue between three participants, Salviati, Sagredo, and Simplicio (representing, respectively, a radical, a conservative, and an agnostic perspective), in which both theories of the universe are apparently discussed impartially.

After being forbidden for years to teach the Copernican theory, Galileo was given the opportunity to express these views by the new pope, Urban VIII, who had been his friend and patron for more than a decade. Galileo was thus granted permission to write a book about the Copernican heliocentric theory, provided that the arguments in favour of the Ptolemaic view were equally debated.

The use of dialogue form allowed Galileo to cast the work as a hypothetical discussion and thus to explore the Copernican model without breaking the parameters imposed by the pope. The censors were easily deceived and in 1630 the book received an imprimatur (printed on title-page verso). Nevertheless, in 1633 Galileo's enemies dragged him to Rome, where he was tried in front of the Inquisition and forced to abjure, while the Dialogo was put in the Index, where it remained listed until 1757. Condemned to life imprisonment, the sentence was then commuted to permanent house arrest.

The Sidereus nuncius had had little circulation since its publication in 1610 and from 1615 Galileo was officially obliged to not express any ideas on astronomy. The Dialogo was then conceived as an appeal to the public (this explains the choice of the vernacular instead of Latin) and as a breaking of this silence.

The work explains all the major recent discoveries in astronomy and proves the correctness of the Copernican cosmological system, refuting what has always constituted the main objection against it, namely the idea that, if the earth revolves around the sun, this should be verifiable through the motion of terrestrial objects, which would inevitably be affected by the earth revolution. Thanks to his investigations into the motion of falling bodies, Galileo demonstrated the falsity of this objection and showed that the movement of the earth makes sense both in terms of astronomy and philosophy (i.e. physics). The Dialogo, more than any other work, made the heliocentric system commonplace.

The Dialogo was quite soon translated into Latin by Matthias Bernegger and published in Leiden and Strasbourg in 1635 (Elzevier press) under the title Systema cosmicum. Reprints appeared in Lyons in 1641, in London in 1663, and in Leiden in 1699. This Latin version greatly contributed to the circulation of the work in the learned world. An English version was printed in London by William Leybourn in 1661. A second edition in Italian was issued in Naples (but with Florence falsely stated) in 1710.

The Dialogo was not included in the first and second editions of Galileo's collected works (published, respectively, in Bologna in 1655-56 and in Florence in 1718), but was rehabilitated for the third edition printed in Padua in 1744. By that time, on the basis of the optical evidence of the earth's revolution around the sun, Pope Benedict XIV had in fact led the Holy Office in allowing the publication of the Dialogo. However, it was only with the Index of 1757 that all heliocentric works were finally redeemed.

Horblit, 18c; PMM, 128; Riccardi, I 511; Norman, 858; Wellcome, 2647a; Carli-Favaro, 128; Cinti, 89; M.A. Finocchiaro, The Routledge Guidebook to Galileo's Dialogue, London, 2014; G. Galilei, Le opere. Edizione Nazionale, Florence, 1890-1909.


We are offering, together with this book, an interesting manuscript letter dated 1641 describing how difficult and dangerous it was to find a copy of Galileo's Dialogo a few years after its publication. The following is a complete transcription of the letter:

“Ill.mo Sig., e P[at]ron[o] mio Colmo. L'obbligo che tengo di servire a V.S. [Vostra Signoria] Ill.ma mi rende quasi che prosuntuoso [sic] in proccurarne l'or[di]ne; [per]tanto esse[ndomi] sovvenuto che li mesi addreto [sic] mi fece V.S.I. fare certa diligenza p[er] il Dialogo del Galileo, che non fu trovato credendo possi haverlo acaro, hò fatto qui p[er]cquisizione e mi è stato provvisto, è però usato, e volgare stampato in Fiorenza delli […?], si compiaccia V.S.I. ordinarmi come devo contenermi à farglielo pervenire, p[er]ché per essere Proibito non mi attento alla semplice posta. Il mio ritorno sarà à ottobre, p[er]ché ho trovate le cose dificultose, essendo li effetti sparti [sic], se V.S. Ill.ma mi farà il favore della l[ette]ra, sarà grand[issi]mo, poi che questa città richiede dependenze di P[at]roni, e Cot[est]a Alt[ezz]a hà il logo primiero app[res]so questi Col[endissi]mi, e a V.S. Ill.ma [per]fine mi rassegno hu[milissi]mo servo facendol rev[eren]za. Venezia, li 29 di Agosto 1641. .S. Ill.ma. Dev[otissi]mo s[uo] servo Franc[esco] Albertinele”.

(“My illustrious Lord, The obligation I have to serve you makes me feel the urgency to fulfill your order; so remembering that months ago you tasked me with finding a copy of Galileo's Dialogo that was not to be found, I performed some research here and procured a copy, used though, of the Italian edition printed in Florence by […?]. Please let me know how I can let you have the book since given that the book is Prohibited I don't trust the regular mail. I will make my return in October, since I have found things difficult […], if my Lord would do me the favour of the letter, it would be great, as this town requires the dependence of Lords, with Your Highness occupying the highest place among the prominent people. I revere my Lord as his humble servant. Venice, 29 August 1641. His devoted servant Francesco Albertinele”).

Bifolium (302x206 mm) written only on first leaf recto. Traces of folding. Very well preserved.

  • Dialogo sopra i due massimi sistemi del mondo
  • Dialogo sopra i due massimi sistemi del mondo
  • Dialogo sopra i due massimi sistemi del mondo
  • Dialogo sopra i due massimi sistemi del mondo
  • Dialogo sopra i due massimi sistemi del mondo