In 1752 Britain at last adopted the ‘new’ Gregorian Calendar because the old Roman or Julian Calendar had become out of step with real time. Many less educated people were upset about the adjustment, thinking they had been robbed of ten or eleven days of their lives. In parts of rural England into the 20th century Old Christmas Day continued to be celebrated on January 5 or 6th – the day it would have been if the calendar hadn’t been changed.
Nowadays ‘mummers’ still go round some villages about this time with their traditional play featuring Father Christmas, and the turning of the season, and the overcoming of darkness by light.
Incidentally, the tree in the medieval apocryphal gospel was originally a date palm.
And finally, in case the old calendar was right after all, Merry Christmas!