That’s by the way why “third reich” is a really bad way to call it: Either call it “drittes Reich” (German) or “third Empire” (English), but mixing the two is just stupid.
If I had to guess this half-way nonsense is probably a result of the English not wanting to be associated with it, giving they kept talking about the “British empire“…
Gibt’s das auch irgendwo in Textform?