pub around 1983? WW2 novel about a GI imprisoned in a mountain castle in Italy

[John]

I am looking for a book I read and was published around 1983 about a GI that either wandered into or was imprisoned in a remote castle in the mountains of Italy. Recall vivid scenes of snowfall outside castle. Was more of an introspective novel than an adventure. I remember buying the book the same day I bought "The Last Supper" by Charles McCarry and both books were new at the time. Desperate to remember and reread this novel 40years later.

[Paige]

Colditz: The Full Story

[John]

Paige wrote: "Colditz: The Full Story"
Thanks Paige, but unfortunately, that's not it. It wasn't a prison in was in, it was an empty castle and he was the only inhabitant and it was more an introspective novel than a tale

[Lobstergirl, au gratin]

Literary fiction or mass market?