[1.09q] Polish: Empire Arcane Temple doesn't require a tech
from 
Elemental Forums
Elemental Forums
In 1.09q empire gold mines and forgotten libraries were changed to require technology to build,
19. Updated Empire gold mine and lost librarys to require techs like the Kingdom versions.
End of quote
However, the kingdom improvement for arcane temples also has a technology prerequisite that the empire version does not have.