This is the most popular Finnish Christmas Carrol. It iscomposed in 1855 by Karl Collan to Z. Topelius' poem "Sylvias hälsningar från Sicilien", (Sylvia's greetings from Sicilia). This song is typically melancholic Finnish mood in minor key and it has a very "Finnish" sound.
The Video:
www.youtube.com/watch?v=CcSCxkprPuo
The Sheet music/tab: