Look towards the fireplace in the room you are standing in.
In the original design of the house, this large room would have been two rooms, to mirror the rooms across the hall. It is unclear if there was ever a full wall dividing this room. The photo above shows the Willard family enjoying reading and playing games in this space.
The house was unfinished when Sylvester Willard purchased it, and he may have left the room as one large sitting room or parlor. The first photographs we have were taken in the late 1870s, after the north addition was completed. You can see in the photo below, that at that time it was one large room, with a curved decorative casing on the ceiling where a wall might have been.
Originally, there were two fireplaces, one on either side of where the current fireplace sits. Many of the furnishings were placed in a symmetrical way between the two halves of the room.
Theodore Case did not undertake any major renovations during his time in the house, however he did simplify the ornate trim work around the doorways and installed the wood paneling in this room. Design in the early 1920s favored more geometric features, rather than the elaborate details of earlier design trends. He replaced the two fireplaces with one central fireplace as well.