You will notice that many things, up to uniform details, are historically correct (or at least more correct, anyway). Our goal was to enhance the historical feel by correcting those oversights. A couple of classical examples are Persian 'Immortals' (who historically had very little to do with how they are depicted in Civ4) and Roman 'Praetorians' (unlike other legionaries, praetorians were never intended for taking part in military campaigns). Original game is in many cases either oversimplifying things, or even plain wrong. It is an open-source community project that is free to download and play, but it requires a legal copy of Sid Meier's Civilization IV Beyond the Sword to be installed. Realism: Invictus is a mod for Sid Meier's Civilization IV that brings a different feel to the game through its realistic visual appearance, deepened game mechanics, refined play balance, and diversity of civilization-specific content.