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I believe this is why some parts of Appalachia still celebrate “Old Christmas” on January 6, which is Epiphany for the rest of the Western church. To my knowled

I believe this is why some parts of Appalachia still celebrate “Old Christmas” on January 6, which is Epiphany for the rest of the Western church. To my knowledge, this doesn’t affect their observance of Easter, which conforms to the Gregorian date.

_delirium 6y ago
The different Easter dates are complicated and not necessarily the same question as Julian vs. Gregorian (though there is a connection). Churches might go either way on the two questions independently. For example, modern Greece is the exact opposite of what you describe for Appalachia: Greek Orthodoxy has adopted the Gregorian calendar, and celebrates Christmas on December 25 every year. But it uses a different ("Eastern Christian") method of calculating the date of Easter, which sometimes coincides with Western Easter, but sometimes can differ from the Western method by as much as 4-5 weeks. I don't fully understand it, but it has something to do with: secular calendars, lunar calendars, and how you compute the date for Passover.
- dhosek 6y ago
  It's even more interesting than you say—the Greeks (and some other Orthodox churches) use the Revised Julian Calendar https://en.wikipedia.org/wiki/Revised_Julian_calendar https://en.wikipedia.org/wiki/Revised_Julian_calendar which aligns with the Gregorian calendar for roughly the millenium spanning 1700–2700. To make this work, they had their own skippage of days in 1923.
  - skissane 6y ago
    The Gregorian and Revised Julian calendars agree up to 28 February 2800. The next day, they begin to diverge – 28 Feb 2800 is followed by 29 Feb 2800 in the Gregorian, but 1 March 2800 in the Revised Julian, and from then onwards the Revised Julian Calendar remains one day ahead. In 2900, they pull temporarily back into synch; in that year, the Revised Julian Calendar has a leap year, but the Gregorian doesn't. In the year 3200, they fall out of synch again, and the Revised Julian once again becomes one day ahead of the Gregorian. I really wonder what the Gregorian-calendar-using parts of the Eastern Orthodox Church are going to do in the year 2800 – assuming they are still around. Will they remember they are supposed to be using the Revised Julian calendar instead of the Gregorian? Or will they decide that being a day ahead of the civil calendar isn't worth the hassle? Maybe by the year 2800 there will be people living on Mars, and maybe even some of them will be Christians, even Eastern Orthodox Christians. I wonder if they will insist on using the Earth calendar, complete with Earth days of exactly 86,400 seconds, and with the boundary between Earth days shifting awkwardly through the Martian day? Or will they adopt a liturgical calendar based on the Martian sol (which is 2219.6 seconds longer than the Earth day)? Do they use the Martian year of 668 sols, or the Earth year of 355 sols, as their liturgical year? The whole Gregorian vs Julian debate, which is still alive in the Eastern Orthodox Church, makes little sense on Mars.
    - dhosek 6y ago
      The whole concept of interplanetary calendars and time keeping will be interesting to see how it's resolved (assuming our species lives long enough for it to matter). It makes the current mess of time zones, daylight savings/summer time and leap seconds seem trivial by comparison. At least the Martian day isn't very different in length from the Earth day, but how will our biology adapt to colonization on a planet where, say, a day is 15 hours or 36 hours?
- skissane 6y ago
  The original Julian calendar, as developed in pre-Christian ancient Rome, had no concept of Easter. But when Christianity became the state religion, the method of calculating the date of Easter became part of the official calendar. Originally Easter was defined astronomically, based on observation of the Moon; however, that posed problems in that different places might make different observations (depending on variations in astronomical skill, and even weather conditions), resulting in different places celebrating Easter on different dates. In the quest for uniformity, they instead introduced a table-based system for determining the date of Easter, based on a simulation of where the Moon should be instead of its actual location. The simulation is based on ancient astronomy, but is less than completely accurate. Hence the date of Easter depends, not on the actual Moon, but rather on a virtual "ecclesiastical Moon". And when Pope Gregory reformed the calendar, he didn't just change the leap year calculation, he also changed the calculation of the position of the "ecclesiastical Moon" to try to make it more astronomically accurate (albeit still inaccurate by modern standards). Hence, there are two different methods of calculating Easter, "Julian Easter" and "Gregorian Easter" – the former uses the original Julian solar calendar, and the original ecclesiastical lunar calendar; the later uses both the revised leap year rule, and the modifications to the ecclesiastical lunar calendar as well. To make it even more complex, when parts of the Eastern Orthodox Church adopted the Gregorian calendar (or strictly speaking the Revised Julian Calendar, which is a slightly different leap year rule which agrees with the Gregorian until 2800), they kept using the Julian calendar (both its leap year rule and the associated ecclesiastical lunar calendar) for calculating the date of Easter. Hence the whole Eastern Orthodox Church celebrates Easter on the same date – which is different from when Western Christians (Protestants and Latin rite Catholics) celebrate it. By contrast, the "New Calendar" part of the Eastern Orthodox Church (e.g. the Church of Greece) celebrates Christmas on the same date as Western Christians, whereas the "Old Calendar" part (e.g. the Russian Orthodox Church) celebrates it on a different date instead.
- Grustaf 6y ago
  Almost all orthodox churches, except the Finnish and maybe Estonian, celebrate Easter in the Eastern way. The correctness of this approach is confirmed every year by the Holy Fire, which doesn't follow the new calendar!
  - rblatz 6y ago
    I was unaware of the Holy Fire, what a neat tradition.
JNRowe 6y ago
I used to have some ex-Soviet country co-workers who took their Christmas break in my January, and I'm sure it was the only time of the year they used that calendar in public. Perhaps in part because of the curious people like us have endless questions about it ;) Wikipedia has an article on the calendar¹, including how and why the movable feasts are calculated. ¹ https://en.m.wikipedia.org/wiki/Eastern_Orthodox_Church_liturgical_calendar https://en.m.wikipedia.org/wiki/Eastern_Orthodox_Church_litu...
- int_19h 6y ago
  Most Russians aren't even aware that this is due to the church using a different calendar - as far as they're concerned, "orthodox Christmas" just happens to be on January, 7 (as opposed to "catholic Christmas" on December, 25). This is further reinforced by January, 7 being a state holiday in Russia - defined directly like that, without any references to the old calendar.
  - lostlogin 6y ago
    Various Christian festivals seem to have taken over from pagan celebrations. The winter solstice is at a similar time to Christmas, and Easter has pre-Christian meaning too. Taking over Christian festivals seems inevitable in that context.
  - Grustaf 6y ago
    Well, many churches use old calendar dates in their church calendars, on websites etc, at least in parallel to the new style. I suppose this might be more common in the diaspora.
    - int_19h 6y ago
      The Russian Orthodox Church calendar is Julian; but keep in mind that church attendance in Russia is low - only about 15% attend at least monthly (for comparison, the same figure is 45% in US), and 35% never go at all. Thus, most believers aren't aware of those details even if they self-identify as Orthodox Christian.
gnopgnip 6y ago
Western Christmas is based on the lunar calendar, the first Sunday after the full moon after the vernal equinox.
- andreareina 6y ago
  You mean Easter?
input_sh 6y ago
January 7th, not 6th, though the day before Christmas is also celebrated. And Easter is affected as well. Sometimes they fall under the same weekend, sometimes they don't. This year it's on the 25th of April. I don't know how exactly the weekend is picked.
- gerikson 6y ago
  Easter Sunday is the first Sunday after the paschal full moon. https://en.wikipedia.org/wiki/Easter#Date https://en.wikipedia.org/wiki/Easter#Date

_delirium 6y ago

The different Easter dates are complicated and not necessarily the same question as Julian vs. Gregorian (though there is a connection). Churches might go either way on the two questions independently. For example, modern Greece is the exact opposite of what you describe for Appalachia: Greek Orthodoxy has adopted the Gregorian calendar, and celebrates Christmas on December 25 every year. But it uses a different ("Eastern Christian") method of calculating the date of Easter, which sometimes coincides with Western Easter, but sometimes can differ from the Western method by as much as 4-5 weeks. I don't fully understand it, but it has something to do with: secular calendars, lunar calendars, and how you compute the date for Passover.

dhosek 6y ago
It's even more interesting than you say—the Greeks (and some other Orthodox churches) use the Revised Julian Calendar https://en.wikipedia.org/wiki/Revised_Julian_calendar https://en.wikipedia.org/wiki/Revised_Julian_calendar which aligns with the Gregorian calendar for roughly the millenium spanning 1700–2700. To make this work, they had their own skippage of days in 1923.
- skissane 6y ago
  The Gregorian and Revised Julian calendars agree up to 28 February 2800. The next day, they begin to diverge – 28 Feb 2800 is followed by 29 Feb 2800 in the Gregorian, but 1 March 2800 in the Revised Julian, and from then onwards the Revised Julian Calendar remains one day ahead. In 2900, they pull temporarily back into synch; in that year, the Revised Julian Calendar has a leap year, but the Gregorian doesn't. In the year 3200, they fall out of synch again, and the Revised Julian once again becomes one day ahead of the Gregorian. I really wonder what the Gregorian-calendar-using parts of the Eastern Orthodox Church are going to do in the year 2800 – assuming they are still around. Will they remember they are supposed to be using the Revised Julian calendar instead of the Gregorian? Or will they decide that being a day ahead of the civil calendar isn't worth the hassle? Maybe by the year 2800 there will be people living on Mars, and maybe even some of them will be Christians, even Eastern Orthodox Christians. I wonder if they will insist on using the Earth calendar, complete with Earth days of exactly 86,400 seconds, and with the boundary between Earth days shifting awkwardly through the Martian day? Or will they adopt a liturgical calendar based on the Martian sol (which is 2219.6 seconds longer than the Earth day)? Do they use the Martian year of 668 sols, or the Earth year of 355 sols, as their liturgical year? The whole Gregorian vs Julian debate, which is still alive in the Eastern Orthodox Church, makes little sense on Mars.
  - dhosek 6y ago
    The whole concept of interplanetary calendars and time keeping will be interesting to see how it's resolved (assuming our species lives long enough for it to matter). It makes the current mess of time zones, daylight savings/summer time and leap seconds seem trivial by comparison. At least the Martian day isn't very different in length from the Earth day, but how will our biology adapt to colonization on a planet where, say, a day is 15 hours or 36 hours?
skissane 6y ago
The original Julian calendar, as developed in pre-Christian ancient Rome, had no concept of Easter. But when Christianity became the state religion, the method of calculating the date of Easter became part of the official calendar. Originally Easter was defined astronomically, based on observation of the Moon; however, that posed problems in that different places might make different observations (depending on variations in astronomical skill, and even weather conditions), resulting in different places celebrating Easter on different dates. In the quest for uniformity, they instead introduced a table-based system for determining the date of Easter, based on a simulation of where the Moon should be instead of its actual location. The simulation is based on ancient astronomy, but is less than completely accurate. Hence the date of Easter depends, not on the actual Moon, but rather on a virtual "ecclesiastical Moon". And when Pope Gregory reformed the calendar, he didn't just change the leap year calculation, he also changed the calculation of the position of the "ecclesiastical Moon" to try to make it more astronomically accurate (albeit still inaccurate by modern standards). Hence, there are two different methods of calculating Easter, "Julian Easter" and "Gregorian Easter" – the former uses the original Julian solar calendar, and the original ecclesiastical lunar calendar; the later uses both the revised leap year rule, and the modifications to the ecclesiastical lunar calendar as well. To make it even more complex, when parts of the Eastern Orthodox Church adopted the Gregorian calendar (or strictly speaking the Revised Julian Calendar, which is a slightly different leap year rule which agrees with the Gregorian until 2800), they kept using the Julian calendar (both its leap year rule and the associated ecclesiastical lunar calendar) for calculating the date of Easter. Hence the whole Eastern Orthodox Church celebrates Easter on the same date – which is different from when Western Christians (Protestants and Latin rite Catholics) celebrate it. By contrast, the "New Calendar" part of the Eastern Orthodox Church (e.g. the Church of Greece) celebrates Christmas on the same date as Western Christians, whereas the "Old Calendar" part (e.g. the Russian Orthodox Church) celebrates it on a different date instead.
Grustaf 6y ago
Almost all orthodox churches, except the Finnish and maybe Estonian, celebrate Easter in the Eastern way. The correctness of this approach is confirmed every year by the Holy Fire, which doesn't follow the new calendar!
- rblatz 6y ago
  I was unaware of the Holy Fire, what a neat tradition.

JNRowe 6y ago

I used to have some ex-Soviet country co-workers who took their Christmas break in my January, and I'm sure it was the only time of the year they used that calendar in public. Perhaps in part because of the curious people like us have endless questions about it ;) Wikipedia has an article on the calendar¹, including how and why the movable feasts are calculated. ¹ https://en.m.wikipedia.org/wiki/Eastern_Orthodox_Church_liturgical_calendar https://en.m.wikipedia.org/wiki/Eastern_Orthodox_Church_litu...

int_19h 6y ago
Most Russians aren't even aware that this is due to the church using a different calendar - as far as they're concerned, "orthodox Christmas" just happens to be on January, 7 (as opposed to "catholic Christmas" on December, 25). This is further reinforced by January, 7 being a state holiday in Russia - defined directly like that, without any references to the old calendar.
- lostlogin 6y ago
  Various Christian festivals seem to have taken over from pagan celebrations. The winter solstice is at a similar time to Christmas, and Easter has pre-Christian meaning too. Taking over Christian festivals seems inevitable in that context.
- Grustaf 6y ago
  Well, many churches use old calendar dates in their church calendars, on websites etc, at least in parallel to the new style. I suppose this might be more common in the diaspora.
  - int_19h 6y ago
    The Russian Orthodox Church calendar is Julian; but keep in mind that church attendance in Russia is low - only about 15% attend at least monthly (for comparison, the same figure is 45% in US), and 35% never go at all. Thus, most believers aren't aware of those details even if they self-identify as Orthodox Christian.

gnopgnip 6y ago

Western Christmas is based on the lunar calendar, the first Sunday after the full moon after the vernal equinox.

andreareina 6y ago
You mean Easter?

input_sh 6y ago

January 7th, not 6th, though the day before Christmas is also celebrated. And Easter is affected as well. Sometimes they fall under the same weekend, sometimes they don't. This year it's on the 25th of April. I don't know how exactly the weekend is picked.

gerikson 6y ago
Easter Sunday is the first Sunday after the paschal full moon. https://en.wikipedia.org/wiki/Easter#Date https://en.wikipedia.org/wiki/Easter#Date