"The Romans have provided a lot of writers with a model for various interstellar empires, of course, and no wonder. The Roman Empire is a really good example of a large empire that, in one form or another, functioned for quite a long time over a very large area. And over all that time, there was all sorts of exciting drama - civil wars and assassinations and revolts and bits breaking off and being forced back in ... But I didn't want my future - however fanciful it was - to be entirely European. The Radchaai aren't meant to be Romans in Space."