My nomination is Alessandro Manzoni's
the Betrothed.
I'm fairly sure it's PD everywhere.
Summary here:
http://en.wikipedia.org/wiki/The_Bet...(Manzoni_novel)
There have been lots of translations, but I cannot find one in Gutenberg.
It's on the kindle, though:
http://www.amazon.com/Harvard-Classi.../dp/B000SP5JLM