@sshubinski,
Has to be wood or Masonite. If it's 19th century, it's not Masonite.
That looks like artboard. This is last half 20th century, any chance this paper applied to the back of a wood or Masonite panel,
I've been looking at the brush strokes, they seem not like what I'd expect to see in an older painting. I wonder if this is maybe a painting devised for a specific someone's interior decor.