Originally, under the Julian calendar, December 25 was the day of the winter solstice and the day Christmas was celebrated. In 1582 the Gregorian calendar was implemented and as such December 25 came a few days later than the solstice event.
*Winter solstice for North America.. summer for the south.
The UK’s National Physics Laboratory made the world’s smallest Christmas card, using platinum-coated silicon nitride. It measures just 15 microns wide. You can fit 200 million of these on a postage stamp.
uxjw: So we can open our presents now?
Istik56: This is incorrect. It has been celebrated on December 25th since the 300s AD, because that was the date of the most popular holiday on the Roman calendar at the time – Sol Invictus. When Constantine concerted the Empire to Christianity, they tried to stamp out the holidays of the popular Sun cults, were met with resistance, and proceeded to convert those too.
Iykury: Actually, by 1582, the calendar had drifted behind the seasons enough that the solstice came on December 11.
criitz: Why should I know this