Forgotten for His
Dancing on the
Graves of Huguenots: Pope Gregory
Pope Gregory XIII 1502-1585
Detail from the
Portrait of Pope Gregory XIII by Scipione
Pulzone, oil on canvas, which made Christie's a
decent 32,500 bucks in 2013.
Ugo Boncompagni was
Pope Gregory XIII from 1572-1585.
He hailed from Bologna, northern
Italy, home of the famous university, which he attended.
Pope Pius IV sent him to attend the
Council of Trent, which
took place from December 13, 1545 - 1563.
Ugo was made cardinal in 1565.
In 1572 he became pope,
succeeding Pope "Saint" Pius V (aka
Antonio Ghislieri, the one who excommunicated
by Pier Paolo Olivieri, Church of
Santa Maria in Aracoeli, Rome
In 1582, Pope Gregory announced a
revision of the calendar. His new version became known as the
New Style Calendar, or the
Gregorian Calendar, and is the one you and I are using today.
Gregorian Calendar, the Julian Calendar,
or Old Style Calendar, was in
Why on earth would you want to mess
with the calendar?
The Julian Calendar figured a year to
be 365.25 days long. It actually is 365.2422 days long. (
Let NASA explain.)
The difference of 0.0078 days per year is not much
in a lifetime (0.624 days for an 80-year-old), but from the time the
Julian Calendar had been implemented up to Gregory's time it was
enough for Gregory to declare that Thursday, October 4, 1582, was to
be followed by Friday, October 15, 1582.
Those living in Roman Catholic
countries and having their birthday between October 5 and 14 were
So, Gregory had the calendar back on
track by fast forwarding ten days. But how to prevent it from
The Julian Calendar already had leap
years, so did Gregory's calendar, but it was more specific: It had all years divisible by 4 marked as
leap years, except for century years, which must be divisible by 400
to be leap years. (Again,
let NASA explain.)
Therefore, the only difference between
the Julian and the Gregorian calendar is that century years can't be
leap years unless they are divisible by 400.
Non-catholic countries hesitated to
commit to the Gregorian Calendar, but eventually they saw it practical to
Here follows the years in which the
countries adapted the Gregorian Calendar:
Protestant German states
1752 - England
and its colonies
1753 - Sweden
1873 - Japan
1912 - China
1918 - Soviet
1923 - Greece
Back to Pope Gregory XIII. When he googled a map, it looked
something like this:
16th Century World Map
of all popes.