This work is in the public domain in Portugal because it is one of the following:

• A photographic work, work deemed to be photographic work or work of applied art created before 1 July 1970 (more info here); or
• Another type of work whose author died before 1956; or
  
• An anonymous work or a work deemed to be anonymous, or a work by a collective person whose authors were not individually identified, published or disclosed before 1956.

This work was published before January 1, 1901 and it is anonymous or pseudonymous due to unknown authorship. It is in the public domain in the United States as well as countries and areas where the copyright terms of anonymous or pseudonymous works are 125 years or fewer since publication.