Painting

My mother bought this painting and has no idea where it came from or who has owned it. It has always been a mystery and because it often looks out of place in the typical living room she always kept it hanging in a back room. We've always joked that she has a rembrandt or that the declaration of independence is hidden in the frame but no one has taken it seriously. Although, it might be a reprint of a popular painting we just don't know. We'd like to know anything about it. Who made it? Who is the subject of the portrait? Where was it painted? When was it painted? Is it valuable and what do we need to do to protect it? Any help would be greatly appreciated by our family. The painting is in good condition although I'm sure it would be much more stunning if it was cleaned and protected. The frame is large and made of a dark wood. The painting has no tears or damage and is in good condition. Here is a picture. Please help!

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