No, Jack, it was definitely a Russian or Czech song I was thinking of--I'm leaning toward Czech.

There's also Pushkin's poem "Uznik" (The Prisoner, 1822), which pops up in both traditional and modern settings. Here's the most famous trad setting:
http://www.youtube.com/watch?v=f-oGsbSdF9I

I think there's also a prisoner song made from a poem by Lermontov. If my neurons start working...