The Old Gods expansion for Crusader Kings II will move the start date for the game back about 200 years to 867 but the development team at Paradox Interactive will still represent Christians as either Catholic or Orthodox in order to simulate the differences between the two power structures.
Chris King, one of the designers working on the game, tells PC Gamer in an extensive interview that, “The Pope has crowned his own Emperor in the West to protect him. And three of the Eastern bishops have fallen to the advance of Islam. So you’re already at this point where the Western church is diverging.”
He also suggests that a number of flavor events will show that the two churches are closer than they will be in the future.
Mechanics might also be introduced to help Christians help each other in battle against the bigger number of pagans that threaten them in the Old Gods expansion.