From time to time, each time at Christmas time, I hear of some Orthodox Christmas or Catholic Christmas. The idea is as great a popular misconception as the bizarre notion which made itself into school textbooks and CIA-administered Wikipedia that the Holy Roman Empire was founded by or in fact has anything to do with Charlemagne.
The Orthodox Church in Russia, an insitutition that was called Orthodox or Right-believers Graeco-Catholic Russian Church (Православная каѳолическая греко-российская церковь), the establishment that is called Russian Orthodox Church was in today's Russia was founded by Stalin in 1943 and in my opinion has little to do with the Empire's Graeco-Catholic Russian Church, also celebrates Christmas on December 24 but the Orthodox Church in Russia uses Julian Calendar - one that was introduced by Julius Ceasar in 48 BC - while the rest of the world and other churches (I think some Orthodox ones like the one Greece which switched a few decades back) use a different calendar, one introduced under Pope Gregory XIII in the year in 1586-1587 when it was adopted in Austria, Spain (then both in a dynastic union?), France, and all states of Italy.
England kept using Julian calendar until 1752, so for almost 200 years from 1587 to 1752 France and Austria had one calendar and England and Russia used a different one (the one that is still used by the semi-official Orthodox church in Russia).
Despite this article (http://www.hermetic.ch/cal_
Merry Christmas to all.