The Question of the Church Calendar

One thing many Westerners know about Orthodoxy is that most of the world's Orthodox celebrate Christmas, the Nativity of the Lord, on January 7 instead of December 25. In fact, most Orthodox in the Western world mark it on December 25.

This issue arises because most of the world's Orthodox, ie, in the Holy Land and most of Eastern Europe, continue to use the Julian Calendar for computation of religious feasts. Since the 1700s the Gregorian Calendar, used first by Catholics, then gradually also Protestants, and later others under their influence, has run ahead of the Julian. Today they are 13 days apart. However, beginning in the 1920s, Churches representing a minority of the world's Orthodox - but a majority of those in the Western world - adopted a Revised Julian Calendar, which for the next several thousand years(!) happens to correlate with the Gregorian.

The upshot is that Gregorian January 7 IS Julian December 25.

And this only marginally touches the issue of Orthodox Easter, Pascha! I still haven't figured out why the West and the Orthodox often end up celebrating the Resurrection of the Lord on different dates!