Wassailing is Christmas caroling. But it was not always thus. Originally it was a contraction of two words meaning, "Good health," accompanying singing and drinking cider, with the last part of the word "wassail" coming from the same root as "hail," meaning healthy.
The phrase was first associated with Twelfth Night rather than Christmas itself, and with a practice of peasants coming to visit their feudal lords, offering their good wishes, while the lord returns the compliment with food and drink.
In researching the roots of Halloween, Thanksgiving, Christmas and New Year's, I was surprised to find a number of connections between these seemingly disparate holidays. Halloween and Thanksgiving both have roots in harvest festivals. Christmas and New Year's both trace their beginnings to celebrations in the dark of winter.
Trick-or-treating and caroling appear to share some history, too. Trick-or-treating is traced to a Scottish tradition of children busking for treats, singing or doing some other form of performing for people in late fall or winter. Eventually London beggars would do something similar.
But historians draw a distinction between outright begging by strangers and the friendly annual meeting of fiefs and serfs as described above, sometimes even citing the lyrics of "Here We Come a-Wassailing," in which the singers say, "We are not daily beggars that beg from door to door / but we are friendly neighbors whom you have seen before."
"The Holly and the Ivy," an English holiday song from the 1700s or earlier, refers to a pair of pagan fertility symbols that were co-opted by the church in England, with both winter plants decorating English churches from the 1400s. The lyrics speak alternately of these plants and of the birth of Jesus, harnessing the existing customs of holly and ivy for missionary purposes.
The poinsettia, by contrast is a fairly new add-on to Christmas celebrations. The plant comes originally from Mexico, and Poinsett was a U.S. ambassador to Mexico who brought it back to the United States. I assume its bright red-and-green colors made it a natural adoption into Christmas decoration, although you can get other kinds.
Modern Christmas came into being in the 1800s. "Twas the Night Before Christmas," actual title "A Visit from St. Nicholas," was published in 1822. James Lord Pierpont, born in 1822, wrote "Jingle Bells" in 1857, though it was originally a Thanksgiving song.
By 1860 Christmas was a legal holiday in 14 states and by 1870 it was a national holiday. Christmas cards date from 1875. The gift giving tradition was originally only for children and one gift was the norm, but an evangelical New York department store owner successfully promoted an expansion of the tradition, also in the 1800s.