Possessory titles are recognized by the courts when they protect a first trespassing squatter against acts of a subsequent trespasser. They are given priority over the claims of the conventional title holder when the latter has lost his right to judicial assistance by reason of acts which raise an estoppel or for failure to act within a period of time which the courts or the legislature have fixed as a limitation of action. In these cases the holder of the possessory title may by court action secure a documentary title in the form of a judgment which confirms a title acquired by estoppel or by adverse possession.
R. G. Patton,
Evolution of Legislation on Proof of Title to Land,
30 Wash. L. Rev. & St. B.J.
Available at: https://digitalcommons.law.uw.edu/wlr/vol30/iss3/13