In
Israel1, December 31 or
New Year's Eve is commonly referred to as
Sylvester.
Nobody knows why...
Then again, it wouldn't be much of a write-up if I didn't check beforehand.
December 31 is known as Sylvester in the name of Pope Sylvester I (AD 314-335). Ol' Sylvie was one of the most notorious antisemites of his day, and backed by The Edict of Milan passed various laws that demoted Jews to second-class citizenship. After the fall of the Roman Empire, the influence of Sylvie's laws spread throughout Europe and became the basis of modern anti-Semitism, the cause for the persecution of Jews during the Spanish Inquisition, etc. The feast of Sylvester I (December 31, the date of his death) has been for centuries an occasion for Pogroms (including the first one ever, on December 31, 1400) and various Jew-mangling activities.
And yet it's still considered a (semi-official) holiday in Israel.
1According to
smartalix, December 31 is called Sylvester in
Germany as well.