“Battle of Wizards” by L. Ron Hubbard
Publication date: May 1949
Original publication: Fantasy Book
Genre: Science Fiction
Story description: When the natives of planet Deltoid refuse to grant mining rights to the Galactic Council, and invasion by force is impossible, a Battle of Wizards is the only option.
Currently available as part of the Stories from the Golden Age series, in the title The Professor Was a Thief.