It is said anything before 1900 is in public domain IF it has had public access. You can, for example, use the Mona Lisa. Music is a bit different since the music itself is not copyrightable but the performance is. Frankenstien maybe copyrighted since Shelling's family may posesses ownership to the original material through her estate. Hercules is not copyrighted but any figure that looks like the guy from TV is copyrighted. Also religious personnas are not copyrighted though maybe be zealously regulated by fanatic sects. There are requirements for items to fall into public domain and there are some items NOT in public domain even though they are before 1900. Peter Pan, for example, has an unlimited copyright on it. A painting by DaVinci in a private collection that has never been exposed to the public is considered copyrighted and owned. But the Mona Lisa is public domain since it is readily viewable in a museum and its image has been made public.