Would an Illiterate Empire ever make it to space

Hope this is right flair.

Just wondering how truly oppressive empires where you can’t read or write can even do well and dominate? Because it seems most maintenance would require some form of education to hold up effectively.

The only examples I know are the Goa’uld and Ori, but they are both more or less the only power in their home galaxies.

So, could an empire that tries to keep an illiterate populace advance and go against other proper powers?