Four Seasons

The Mahril (1365-1427) had only the

Julian calendar . 60 days* from the

Tekufah** was November 22.

In 1582  the Gregorian calendar was

introduced. 60 days from the Tekufah

is Dec.4. (until 2100 then it will be Dec.5)***

* תניא, חנניה אומר, ובגולה - עד ששים בתקופה

(Ta'anis 10a.) 

* *According to Shmuel ( Eruvin 56a) each 

Tekufah (season) has 91 days & 7.5 hours 

x 4 = 365 days &6 hours (year)

***every 100 years it keeps moving up by

a day, except for a century that is divisible

by 400 example 2,000 (in the year 2000

we didn't move to the 5th)