The frontispiece of the Dialogue

On 7 June 1630, during his stay in Rome, Galileo submitted the frontispiece of "Dialogue" (external link) to Pope Urban VIII. The Catholic authorities compelled him to change the original title (which unfortunately is not precisely known to us). Galileo wanted to emphasise that the Dialogue was actually about the tides (ebb and flow). The astute and cautious wording of the title was intended to make people believe that Galileo at no time wanted to take a stand on either the Copernican or the Ptolemaic world system. But the committee specifically appointed by the Pope concluded that Galileo was unequivocally inclining in this work in favour of the mobility of the Earth and immobility of the Sun.


Rare Books. Rar_4346.

Frontispiece of the Latin edition

The title "Systema cosmicum" (external link) of the Latin edition is the actual working title with which Galileo himself had been designating his project at least since 1610. The Latin edition also contains the famous letter to Christina of Lorraine of 1615 in which Galileo attempts to reconcile the Copernican system with Holy Scripture.

Systena Cosmicum

Rare Books. Rar_4030:1.