Mantel top

This item was in my great Grandfather's home. I think he either purchased or traded for it from a late 1800 or early 1900 home that was to be torn down to build a road. I have never seen another mantel top such as this. I don't know the style or period, but it still has the original mirrors. it has no identifying markings that I could find. I would just like to get an idea of where this could have been made, how common is this style/type of mantel top, or at least that is what it has always been used for since it was in my great Grandfather's home