"Over 100 years old" -- probably not. "Almost 100 years old" -- that's more accurate. It looks like a Jacobean Revival chair from the '20s or early '30s. The geometric back puts it more in this time frame than in the earlier Jacobean Revival style. It is very sweet, looks comfortable, and has great charm -- and in a few short years, it WILL be over 100 years old!

BUT....it's also a chair..... And while it might not have the salability as an antique one may wish....it's still a usable piece of furniture. You could sell that chair for just what you paid....but then you will have to go buy something to take it's place. Antiques that serve a purpose are different to me than those things you buy and stick in a cupboard in hopes that they will appreciate in value....or worse yet....collecters items. I have a round oak table....bought a long long time ago, before the golden oak boom....so I got a huge bargain. They the bottom dropped out of the golden oak market, and not many years later that table is now worth about 10 times what I paid. If I had invested the money I paid some 45 years ago....likely I would have had more than I could sell that table for....BUT....all these years I have had a table for eating, for homework for projects.......and it's still worth about 10 times what I paid. Linda C

From what little I can see (could we have a picture of the whole chair), it seems your grandfather is correct -- 1860-1870, Eastlake influence, possibly walnut. Is it a platform rocker?

P something & Co is all I can figure out. May be manufacturer or the retailer. The messed up finish is probably a mix of old linseed oil and beeswax polish, body oils and dirt. Try cleaning it with mineral spirits and settl wool to get the grunge off and see what it looks like.