SALEM, Ore. (AP) — More than 5,300 people were cremated at Oregon's state mental hospital between 1913 and 1971. Two-thirds of them were never claimed, their remains abandoned inside copper canisters that were discovered a decade ago in a shed.

They were dubbed the "forgotten souls." A research effort to unearth the stories of those who moved through the hospital's halls, and to reunite the remains with surviving relatives, takes center stage Monday as officials dedicate a memorial to those once-forgotten patients.

Hospital officials have been working for years to reunite the remains of their former patients with surviving relatives. Since the urns were found by lawmakers on a tour of the hospital in 2005, 183 have been claimed.

The 3,400 that remain are listed in a searchable online database.