52 Chapter 3
between the Julian calendar and the observed astronomical occurrences of solstices and
equinoxes.^33 Zarlino thus entered into two intricate calendrical disputes, about which his
texts show his close study, evidencing his definite awareness of contemporary issues of
astronomy. In his time, the Julian calendar was about two weeks in disagreement with the
astronomical seasons: Julian March 21 fell two weeks shy of the observed vernal equinox.
To remedy this, Zarlino proposed adjusting the calendar by twelve days (in 1582 a ten-day
shift was adopted, along with the present scheme of leap years).
Even more to the point, Zarlino owned a copy of the first edition of Copernicus ’ s De
revolutionibus , which Zarlino signed and dated 1566.^34 This places Zarlino in an elite
company of astronomers and savants who bought this rather expensive book when first it
appeared. Compared to the wider distribution of the extant copies in German-speaking
lands, Zarlino ’ s copy represents a notable point of contact for Copernican ideas in Italy.
Based on the altogether geocentric descriptions in his Istitutioni , we infer that Zarlino
was not convinced by Copernicus. If Zarlino acquired his copy of Copernicus during or
before the 1560s, when Vincenzo studied with him, it seems plausible that Zarlino may
have mentioned it to him, if only as a curiosity. If so, one wonders about their ensuing
discussions, for at some point Vincenzo seems to have decided that Copernicus was
correct. The musical justification he gives in his Dialogue suggests that he thrashed out
the matter in the course of his studies with Zarlino, or in the subsequent years. Did they
argue about Copernicus? Did Vincenzo ’ s rebelliousness move him to sympathize with the
heterodox cosmology, if only to annoy his mentor? Vincenzo certainly came to disagree
with his teacher on many matters, bringing them forward both in the Dialogue and in his
later Discorso intorno l ’ opere di Messer Zarlino ( Discourse on the Works of Mr. Zarlino ,
1589). Though at the beginning of his Dialogue Vincenzo paid homage to Zarlino as “ one
of the masters ” alongside Gafurius and Glarean, his scathing criticism of what he consid-
ered his teacher ’ s errors about Greek music was so brusque that Zarlino took offense at
what seemed Vincenzo ’ s ingratitude and disrespect.
Though these disputes had to do with musical matters, Zarlino could have been the
source for Vincenzo ’ s awareness of heliocentrism, based on his possession of Copernicus ’ s
book. There is another, not completely distinct possibility. Galileo Galilei was a teenager
during the years leading up to his father ’ s Dialogue and later recorded in his own Dis-
courses on Two New Sciences his awareness of some of the musical issues that engaged
his father. Knowing that Vincenzo had adopted the heliocentric view sometime before
1580, it seems plausible that he and Galileo discussed it. If so, Galileo might have learned
of this new astronomy from his father. Writing to Kepler in 1597, Galileo remarks that he
had “ many years ago ” adopted Copernican views, though he does not specify how long.^35
Placing his first contact with it during the 1570s would certainly fit this description, giving
fully twenty years in which he could have mulled it over. Given the generally positive
tenor of Galileo ’ s references to his father, one might speculate that he took up his father ’ s
enthusiasm for the new cosmology during the period in which the Dialogue was being