The "Huron Carol" (or "Twas in the Moon of Wintertime") is a Canadian Christmas hymn(Canada's oldest Christmas song), written probably in 1642 by Jean de Brébeuf, a Jesuitmissionary at Sainte-Marie among the Hurons in Canada.[1] Brébeuf wrote the lyrics in the native language of the Huron/Wendat people; the song's original Huron title is "Jesous Ahatonhia" ("Jesus, he is born"). The song's melody is based on a traditional French folk song, "Une Jeune Pucelle" ("A Young Maid"). The well-known English lyrics were written in 1926 by Jesse Edgar Middleton
Theres the wiki bit. I didn't know all that - young children enjoy this Carol - its range is not too bad and the rhythmic side appeals to a class of young children