"Ding Dong" was composed as a French dance tune in the 16th century. A 19th century Englishman added lyrics that made it a Christmas tune. It was first published as part of a book of carols in 1924. From Wikipedia: "The song is particularly noted for the Latin refrain: Gloria, Hosanna in excelsis! (Glory! Hosanna in the highest!), where the sung vowel sound "o" of "Gloria" is fluidly sustained through a lengthy rising and falling melismatic melodic sequence, extending the word to a 33-syllable-long lyric." Luckily, since this is purely an instrumental, you don't have to sweat the meaning of "melismatic melodic sequence."
This arrangement is for two trumpets, horn, baritone TC and tuba.
Score and parts are available for a modest price at halleonard.com. Search on my name (Will Corbin) for the entire collection.