An ancient ceiling fan
We gotta admit that that dinner set looks absolutely stunning. However, the main object isn’t of the dinner set itself, despite being the focal point of this shot. In fact, it’s the weird contraption above the table that left the OP pretty confused.
An expert on historic dining rooms or something informed the OP that this was an old-fashion ceiling fan. By pulling on a rope, the rectangular object would swing back and forth to shoo away flies. The homeowner had to keep the fan clean at all times or dust would fall onto their plates and into their glasses.