Historically, this was knight-poet of the Middle Ages. They wrote poems about chivalry and love. They’re the ones responsible for the image of the gallant knight on the white horse rescuing the damsel in distress.
In more modern times, a “troubadour” is a singer of folk music. I’ve heard many musicians – usually more traditional, lyric musicians – referred to as troubadours (think Tony Bennett, Michael, Buble, etc.)
Why I Looked It Up
It was used several times in The First World War. The book had a peculiar focus on war poets – apparently a lot of poetry came out of that war (including “In Flanders Fields,” one of the most famous war poems).