Pre-1837, Christmas was not celebrated as we do now. Winter feast days (wassailing, Plough Monday, etc.) tended to be local and between All Hallows (1st Nov.) and Candlemas (2nd Feb.). In England, Christmas was an invention of the Victorian middle class; Presbyterian Scots saw it as essentially pagan, and celebrated Hogmanay.
Middle class fashion for charity giving at Christmas replaced the Christmas Box; a centuries old tradition for masters and householders to give money to servants and tradesmen rewarded loyal customers with free goods. The Christmas tree is a German custom popularised by Prince Albert.
Twelfth Night was still observed, but over time the focus concentrated on Christmas Day and Boxing Day as essentially family festivals rather than a village event, so many rural customs died out.
Annual greetings were exchanged at New Year, which was never a religious festival. In 1843 Henry Cole began printing Christmas cards. The first designs were often pagan, with nymphs, etc. In 1840 sweet-maker Tom Smith invented the cracker as a sales gimmick. Originally a wrapper with a bang for sweets, they sold better when he added paper hats and trinkets.
Swan or goose were originally the birds for a feast, with lower income families having a beef joint. Turkeys probably first came via the Spanish, who had brought them back from the Aztec Empire. Some may have been introduced by William Strickland; his family crest (granted c. 1550) has a turkey as a crest. Henry VIII is the first known king of England to eat turkey. Mince pies date from Elizabethan cookery. Christmas cake was originally the Twelfth Night cake.
December 25th became Christmas Day when the church took over winter solstice celebrations. Many winter celebrations were raucous and ribald, until Victorian middle classes favoured family-centred events. The cross-dressing of Twelfth Night transferred to pantomime (the dame) and risque jokes.
St Nicholas, Bishop of Myra in Turkey, became the patron saint of children in the 5th century; his name evolved into Santa Claus. Pre-1870, Father Christmas was a regular character in mummers' plays, representing revelry and festivity. Early pictures show him in green robes but these changed to red bishop's robe with the link to St Nicholas. The two terms are now interchangeable. An 1822 poem by Clement Clark Moore first described him and the eight reindeer.
The days following Christmas Day are known in the church as the season of Epiphany (or Tiffany to country folk). King Alfred is said to have made a law making the twelve days of Christmas into a season of festivals called Twelvetide or Twelfthtide and feasting and celebrations were held during the period until the final revel on Twelfth Night. This took place on the night of 5th Jan into the early hours of 6th Jan. We have forgotten the ancient custom of starting the day not at midnight but at six pm. Twelfth Night (5th Jan.) therefore precedes Twelfth Day (6th Jan.) when decorations would be taken down - as many people still do today.
Hogmanay may be derived from Norse and Gaelic observances of the winter solstice. As well as Scotland, it was celebrated in the far north of England. Customs vary in Scotland, but usually include gift-giving, visiting the homes of friends and neighbours. The first-foot (the first guest of the year, a tall dark male is preferred), traditionally brings symbolic gifts such as salt, coal, shortbread, whisky and black bun (a rich fruit cake) to bring good fortune to the household. Auld Lang Syne was composed by Robert Burns in 1788 and set to a traditional folk song.
Sources: various.