Position of intercalary day in February in late 16th C.
> If I am not mistaken, the leap day was not moved from the 25th to the
> 29th by Pope Gregory's bull That only happened in the British Empire
> when Parliament reformed the calendar in 1753
Section 9 of "Inter Gravissimas" says:
"Anno vero MM, more consueto dies bissextus intercaletur, Februario
dies XXIX continente, idemque ordo intermittendi intercalandique
bissextum diem in quadringentis quibusque annis perpetuo conservetur."
"Assuredly, the year 2000, as with our custom, will have a bissextile
intercalation, February will contain 29 days, and the same rule of
intermittent bissextile intercalations in each four hundred year period
will be preserved in perpetuity."
It's true that the bull does not say that the position of the extra day
in a leap year was to be moved from the day before February 25th to the
day following February 28th. That is because when the bull was issued
the extra day was already the day following February 28th, at least, if
we can believe Wikipedia, which says
"During the late Middle Ages [1250 to 1500 CE] days in the month came
to be numbered in consecutive day order. Consequently, the leap day was
considered to be the last day in February in leap years, i.e., 29
February, which is its current position."