The Berne Convention stipulates that the term of copyright protection is the life of the author plus at least 50 years after his death.
The member states of the European Union, following a directive, increased the term for the author's life by another 70 years after his death.
In the case of an unknown author, 70 years from the date of release.
All works released until 1929 have expired copyright and are therefore available in the public domain.