The Boar's Head Festival

from: https://cincinnaticathedral.com/boars-head-tradition/

edited for length

This pageant is rooted in ancient times when the boar was sovereign of the forest. A ferocious beast and menace to humans, it was hunted as a public enemy. At Roman feasts, boar was the first dish served. Like our Thanksgiving turkey, roasted boar was a staple of medieval banquets. As Christian beliefs overtook pagan customs in Europe, the presentation of a boar’s head at Christmas came to symbolize the triumph of the Christ Child over sin.

The festival we know today originated at Queen’s College, Oxford, England in 1340. Legend has it that a scholar was studying a book of Aristotle while walking through the forest on his way to Christmas Mass. Suddenly, he was confronted by an angry wild boar. Having no other weapon, the resourceful Oxonian rammed his metal-bound philosophy book down the throat of the charging animal, whereupon the brute choked to death. (Remember that tidbit before being rude to a librarian or bookseller!) That night the boar’s head, finely dressed and garnished, was borne in procession to the dining room, accompanied by carolers singing “in honor of the King of bliss.”

By 1607, an expansive ceremony was in use at St. John’s College, Cambridge, England. There, the boar’s head was accompanied by “mustard for the eating” and decorated with flags and sprigs of evergreen, bay rosemary and holly. It was carried in state to the strains of the Boar’s Head carol.

By then the traditional Boar’s Head Festival had grown to include lords, ladies, knights, historical characters, cooks, hunters, and pages. Eventually, shepherds and wise men were added to tell the story of the Nativity. The whole was embellished with additional carols, customs and accoutrements. Mince pie and plum pudding, good King Wenceslas and his pages, a yule log lighted from the last year’s ember, all found a place and a symbolic meaning in the procession.

Other takes (Wikipedia)

1. Old Edwardian Club, Stourbridge, West Midlands. The Boar's Head supper was traditionally celebrated on Christmas Eve since 1911 but is now celebrated on 23 December. The decorated Boar's Head, carried on a platter by the club's president, is ceremonially presented to the members. After the welcome and seasonal greetings, a supper is served, which includes brawn-filled bread rolls.
2. The Queen's College, Oxford, Oxfordshire. William Henry Husk, librarian to the Sacred Harmonic Society, wrote about the tradition in his Songs of the Nativity Being Christmas Carols, Ancient and Modern (1868): Where an amusing tradition formerly current in Oxford concerning the boar's head custom, which represented that usage as a commemoration of an act of valour performed by a student of the college, who, while walking in the neighbouring forest of Shotover and reading Aristotle, was suddenly attacked by a wild boar. The furious beast came open-mouthed upon the youth, who, however, very courageously, and with a happy presence of mind, thrust the volume he was reading down the boar's throat, crying, "Græcum est," and fairly choked the savage with the sage.
3. The Queen's College celebrates the tradition by three chefs' bringing a boar's head into the hall, with a procession of a solo singer who sings the first verse, accompanied by torch bearers and followed by a choir. The procession stops during verses and walks during the chorus. The head is placed on the high table, and the Provost distributes the herbs to the choir and the orange from the Boar's mouth to the solo singer.

The Boar's Head Carol

The carol includes macaronic verse, a mix of languages. I.e., Latin and originally Middle English. Three verses are commonly sung. An additional three verses have been known to be added.

The boar’s head in hand bear I,

Bedeck'd with bays and rosemary; (pronounced rose-meh-rye)

And I pray you, my masters, be merry, (pronounced mehr-rye)

Quot estis in convivio. [Howsoever many are at the feast]

Caput apri defero, [the boar's head I offer]

Reddens laudes Domino. [rendering praises to the Lord]

The boar's head, as I understand,

Is the rarest dish in all the land;

Which thus bedeck'd with a gay garland,

Let us servire cantico.  [Let us serve with a song]

Caput apri defero,

Reddens laudes Domino.

Our steward hath provided this

In honor of the King of Bliss;

Which, on this day to be served is

In Reginensi atrio. [in the Queen's (College) hall]

Caput apri defero,

Reddens laudes Domino.