1 Introduction: De motu and its fortune
The so-called De motu appeared in 1642, after Galileo’s death when Vincenzo Viviani, the last follower of the great Pisan scientist, decided to collect all his writings in order to:
[...] reprint all Galileo’s works in the form of sheets with greater fullness and magnificence in two columns for the two languages, the former Tuscan, in which the author wrote, the latter Latin to be translated by some of our compatriots and lastly with the addition of a great number of writings by the same author which I gathered from different parts with great difficulty. [Viviani 1674, 104-105], [Favaro 1885, 19, 158-159, my translation]
This was an onerous but rather heartfelt task and led him to happen on some papers by Galileo collected in quinternions entitled De motu antiquiora while he was working on the bibliography of a major study on the fifth book of Euclid’s Elements. Viviani immediately thought they were early studies of the Master about motion, alr...