Bradt believed his backyard ran all the way to a fence. Actually, a strip on Bradts side

Question:

Bradt believed his backyard ran all the way to a fence. Actually, a strip on Bradt’s side of the fence belonged to his neighbor Giovannone, but Bradt never intended to take land away from anyone. Bradt later brought an action against Giovannone to determine who owned the strip on Bradt’s side of the fence. Who is the owner? Why? [Bradt v. Giovannone, 315 N.Y.S.2d 96]