I have a painting which is painted on the revers side of a glass sheet it is app 100 Years who can help info?

The painting is done on the back of glass and is of a castle and a stream with a little figure standing with his back to us . Beside himand the stream is what looks like a old farmhouse .So the castle is high on a hill and the stream is in the middle farm beside the stream we can find no signiture or mark of who painted it.is this usual or do some glass painters not sign work 20″X20″ where would one go to get more info please. thank you for the dutch sites very good.