Very Old Piece of art, painting, picture

It's a painting of what I consider a mother and daughter picture painting with no signature or at least not one I can find. I was taking care of a man and he said it was passed down in his family. When he died 23 years ago at 101 years of age he left this to me because I loved it so much and never shut up about it. It's got some water marks on the back. I'm not quite sure what it's painted on but I included a picture of what the material is that it's painted on. It has some damage on the painting which would bring the value down on the painting however I would still like to know who painted it, and what the value on it is, if any. I would think it's worth something if I've had it myself for 23 years and the man whom died at the age of a 101 had it for many many years becaused it was passed down to him form his family. A painting that old must be worth something. There's not much more I can say on this painting except for I have enjoyed the beauty of it for many many years and am going to continue to enjoy it. It has brought peace to me in many ways. I have been wanting to get an appraisal for many years but am just now getting around to it. Now that's there's technology invented to find this stuff out. Please anyone out there who may know ANYTHING about this please get back to me. Knowing it's history would make the painting all the more interesting to me.