Antique Oil Painting On Porcelain, Children Portrait, Ornate Period Frame

This is an incredible oil portrait of two young children. It seems to be done on porcelain and has a very unusual convex wooden backing. As you can see, all of the nails are hand hammered holding it together. It has a beautiful period frame with so much detail. The portrait itself is very well executed. It is dated early 1800s - if not earlier. The painting itself is in very good condition. It appears to be unsigned.The frame measures about 14" wide by 17" tall. It has some wear and damage from age - some chips and nicks. It is still very ornate and has a ton of character. The portrait is about 4.5" wide by 6.75" tall within the frame.Please feel free to reach out with any questions.