That is was composed by Johann Pachelbel and is called the Canon in D.
Pachelbels Canon in D is not Christmas music. Perhaps someone has combined this piece with something else, but it wouldn't have been composed by Pachelbel.
One is the Concerto for Two Violins in D Minor by Bach. It is a duet that sounds pretty good.
Pachelbel's Canon in D has influenced numerous songs across various genres. Notably, it appears in "Go West" by the Pet Shop Boys, "All of Me" by John Legend, and "With or Without You" by U2, where its chord progression is utilized. Additionally, many pop and classical crossover pieces have drawn inspiration from this iconic composition. Its enduring popularity continues to inspire new interpretations and adaptations.
Pachelbel's Or Canon in D, by Pachelbel.
There are reasonably good keyboard versions of the Canon in D.
Look up "Canon in D major for violins" in a serach engine.
Pachelbel's Canon (Canon in D Major by Johann Pachelbel)
The chords for "Canon in D" by Pachelbel are D major, A major, B minor, F minor, G major, and G minor.
The chords for Pachelbel's Canon in D are D major, A major, B minor, F minor, G major, and G minor.
Canon in D is Pachelbel's most famous composition. It was composed in early 1600's. It is paired with a gigue in the same key.
Some musical bands that incorporated the melody of Pachelbel's Canon in D in their songs include "The Pop Tops" and "Aphrodite's Child." You can learn more about Pachelbel's Canon in D at the Wikipedia.
Canon in D