Une Jeune Pucelle is a French folk song from 1557, which has a melody that is based loosely on an older French song entitled Une Jeune Fillette.

Une Jeune Fillette is itself based on an Italian ballad from 1465, entitled "La Monica".

St. Jean de Brébeuf brought the Une Jeune Pucelle melody to the Toronto

Toronto

Toronto is the provincial capital of Ontario and the largest city in Canada. It is located in Southern Ontario on the northwestern shore of Lake Ontario. A relatively modern city, Toronto's history dates back to the late-18th century, when its land was first purchased by the British monarchy from...

 area (Toronto, Ontario, Canada) around 1643, and set it to new lyrics as Huron Carol

Huron Carol

The "Huron Carol" is a Canadian Christmas hymn , written in 1643 by Jean de Brébeuf, a Jesuit missionary at Sainte-Marie among the Hurons in Canada. Brébeuf wrote the lyrics in the native language of the Huron/Wendat people; the song's original Huron title is "Jesous Ahatonhia"...

(Twas in the moon of wintertime...).

This melody was later used by Huron Carol ("Twas in the Moon of Wintertime) in the 18th century.
Une Jeune Fillette

Lyrics

Une jeune pucelle de noble coeur priant en sa chambrette
Son createur, l'ange du ciel, descendit sur la terre
Lui conta le mystere de notre salvateur,
ce Dieu si redoutable est homme comme toi,
est homme comme toi.

Entend ma voix fidelle, pasteur, suis moi.
Viens témoigner ton zèle au divin Roi;
Ce Dieu si grand est né dans une étable,
Ce Dieu si redoutable est homme comme toi.
est homme comme toi.