Zither
He was a cabinet maker he also works with a prince he was born in the 1700s
This is an antique, circa 1900, zither instrument with affixed label for the maker Georg Haupt. The label appears to be in German, and the maker name is generally associated as Swiss. There was a Swiss furniture maker of that name, though this is not the same person. Zithers, though antique are a bit of a hard sell on the market. The estimate is based on actual recent past recorded auction sales of comparables.
Please add a clear, in-focus, well-lit close-up image of the label inside the instrument.