There's none. But the validity of a copyright of a work is dependent on the place in which you're applying the law, not on the place where the author is from (except when applying the rule of the shorter term).
Tons of works are in the public domain in one country, but not another.
The oldest still in effect copyright I know of is from 1611: the King James translation of the bible is still copyright of the crown in the UK. No other country recognizes that copyright.
> The oldest still in effect copyright I know of is from 1611.
I can beat that by over 4000 years.
As far as Icelandic copyright law is concerned the copyright on the
Diary of Merer[1], written 4500 years ago, will be held by the French Egyptologist Pierre Tallet until 2039.
This is because the copyright protection commerces when the work is made available for sale, loaning out etc. to the public.
If you discover a previously unpublished work that's not protected by copyright you get to enjoy 25 years of copyright protection, i.e. the copyright is assigned to the person who discovered and published the work.
I only have a source in Icelandic, it's article 44 of the copyright act [2].
The 25-year rule is part of an EU copyright directive (which Iceland, as an EEA country, has adopted as well). Also, this isn't technically a copyright, but an equivalent right. (And the right is not 4000 years old.) The EU directive says (in English):
> Any person who, after the expiry of copyright protection, for the first time lawfully publishes or lawfully communicates to the public a previously unpublished work, shall benefit from a protection equivalent to the economic rights of the author. The term of protection of such rights shall be 25 years from the time when the work was first lawfully published or lawfully communicated to the public.
The KJV is protected in the UK by Royal Prerogative rather than by copyright law. The KJV rights are actually older than copyright in the UK.
A number of countries have copyright restrictions on things of national significance, etc., however, and then there's the concept of domaine public payant.
Tons of works are in the public domain in one country, but not another.