The 'zodiac' or calender pages of the Voynich Manuscript are among the most popular features of the book. For some bizarre reason the pages for January and February are missing and we have extra folio with April and May. The idea that the Voynich Manuscript may be the book captured from Charles VIII at the Battle of Fornovo may provide a story behind the VMs calendar.
The Italian affair of Charles VIII starts officially in March 1494 when the French King declares his intentions to occupy Naples. The first folio of the VMs calendar is March/April fol. 70r/v.
At this time the French are stationed in Lyon, where they are preparing for the campaign.
The next folio represents April and May and is most likely misplaced - it was meant for April-May next year (1495).
The correct order, in my opinion, is fol. 70 March/ April followed by the foldout including May,June,July,August,September and October.
During this time Charles VIII receives the invitation from Milan with pledge of support so in August/September 1494 the French are crossing the Alps. Charles VIII becomes ill at the time of his arrival in Asti, but continues forward. In September he receives the title Byzantine Emperor from Andreas Palaiologos (who later sells it again to Spain).
Next comes the VMs folios 73r/v representing November and December.
Charles VIII entered Florence on November 17th and Rome on December 31st 1494.
Here comes the gap in the VMs callendar. Charles VIII stays in Rome for a month and it seems all is well and over. At this time the King of France (and new Byzantine Emperor) is living his imperial dream.
There is no entry in the VMs calendar for the next three months - January, February and March of 1495 when all is triumphant for the French - Charles VIII entered Naples on February 22, 1495.
The calendar resumes with fol. 71r/v representing April and May of 1495. What prompted the resuming of the calendar? On March 31, 1495 the Holy League announces their challenge for Charles VIII - his return home will go through battlefields.
On July,6 1495 is the Battle of Fornovo where the book is captured.
It may not be what it is, but it sure makes a nice story.
UPDATE: Nick Pelling, who did extensive research on the order of the pages of the Voynich Manuscript, assured me that the calendar pages are in right order. Fol. 71 r/v is part of the same parchment sheet as fol. 72 r/v. So there is another reason for the extra rosettes for April and May.