What is the name of this music from the Grand Theft Auto Online Christmas tree?

The bunker Christmas tree in Grand Theft Auto Online plays music. I can recognize Deck the Halls and Jingle Bells, but I don't recognize the third one. It's instrumental music only, which you can hear at 27 seconds in this YouTube Video:


Solution 1:

It is The Boar’s Head Carol, a 15th century English Christmas carol.

Wikipedia has samples here:

  • A Carol Brynging in the Bore's Heed
  • The Boar's Head Carol