Bellum Imperii is an complete overhaul modification for M&B: Warband. It represents ancient Europe and parts of Africa and Asia during Marcus Aurelius reign of the Roman Empire.
I went into this mod thinking it was one of the mediocre ones that you play for an hour and then never really play again. Boy was I wrong! Instead of boredom, you're greeted with an excellent character creation screen that has tons of options to really make a unique character, great art and equipment, INCREDIBLY awesome music that will pump you up and never leave you feeling bored, a map that really feels authentic, lots to do, and combat that feels somehow more fun than what you'd normally encounter in a mod. This is the best early stages mod I've ever played, and not only that, but it's the best MOD I've ever played. Keep up the incredible work, and I'll keep on playing :D
EDIT: It was also a great idea to build on top of Brytenwalda.