Civ IV in fact has slightly less combat units than were present in Civ III, pointing to a move away from the dominating role of war in previous games. The change is not drastic - conquering the world by force is still very much an option. But the key word is option. Civilization IV makes more peaceable roads to victory both viable and gratifying. (The latter Civ III failed to achieve, in my opinion - cultural victories always felt like an abrupt and unfulfilling end to the game.) This is due in part to the more exciting and vibrant world created by the 3D engine, but credit must also go to the changes in game rules and dynamics. For instance, excessive expansionism is no longer always advisable - there are penalties for having large numbers of cities. Furthermore, the 'war' of culture has been made far more interesting by the inclusion of features like religion.