Happy Christmas, Everybody!
The first Christmas Day was instituted by Constantine the Great in 336 A.D. The Day was that of Sol Invictus, the final day of the feast of Saturnalia, and was designed to bring the two cults into alignment, as both were popular in the Roman army.
He was, of course, using the Julian Calendar, set up by Julius Caesar in 45 B.C. to replace the older Roman Calendar.
The years rolled on, and it became more and more obvious that even this calendar was not sufficently accurate, so, to correct the errors, the Gregorian Calendar was introduced. Catholic countries took it up in the 16th century, the US, Canada and the UK in 1752. They did so by subtracting 11 days from the Calendar; this was on September 2nd of that year, so that the following day became the 14th of September, 1752 A.D. The new, Gregorian January 6th, was now in the slot vacated by December 25th which was now earlier!
How long is this "Season of Christmas" then?
Like many Christian festivals there are variables involved! These occur at the beginning, at Advent, as it is not a constant. It does NOT commence always on Dec.1st, although it does happen to do so next year. This year it was on Dec.2nd.
It begins on the third Sunday before Christmas Day, so the earliest date it may be is Nov.27th and the latest is Dec.3rd.
It therefore follows that many "Advent Calendars" are totally wrong. They were not introduced until the 19th Century anyway, and the idea of having a chocolate for each day was a marketing ploy introduced in the 1950s; abolition of sugar rationing helped there, of course. It works on the usual system: children may be relied upon to prise money out of adults!
The third Sunday is also known as "Gaudete (Rejoice) Sunday".
https://www.youtube.com/watch?v=l1NgHonWNE0
My favourite Advent carol, but not singable by a congregation!
The 12th Day of Christmas, Jan.6th is Epiphany as we all know, but it is NOT the end of the Christmas Season.
Also centred on the Birth is an ancient Jewish ritual of Purification after a birth. The mother was supposed to go to the Temple for this, so Feb.2nd, known as Candlemas, is this Day - and it is 40 days from the Birth as the old system decreed. We know Candlemas as the "Feast of the Presentation of Our Lord".
Removing the decorations? This depends on the country, some using Epiphany and others using Candlemas.
In the UK it may be either or both! Our Crib will come down on Candlemas and the tree on 10th January, after the 10:15 a.m. Mass. (We have the tree for the children as it is not part of tradition.)The date is chosen because of transport availability. It's a large tree.
To clarify this: The two dates are first and last dates, earliest and latest, so decorations may be removed on any day between these two extremes as well.
Of course, as today was January 6th, we added the Magi to the Crib as they may not be there earlier. That's why it cannot be removed until after the 6th.