Conn Iggulden said this quote

The world has grown too large for one army of the nation, my brother. You will ride where I tell you to ride, conquer where I tell you to conquer. The world is yours, if you can put aside the base part of you that tells you to rule it all. That you may not have. Now give me an answer and your oath. Your word is iron, brother, and I will take it. Or I can just kill you now.