The basis of most economies at the time (in particular, the economies simulated by CK2) was land. In particular, the republics provided two vital components every crusading army required: money and ships. These republics (especially Venice, Genoa, and Pisa) played a large role in the success and failure of the different Crusades. It is the aim of this expansion “Crusader Kings 2: The Republic” (CK2:R) to add these vital players to the game. Given this focus it was odd that the original game did not allow one to play as any of the merchant republics. One could always play as Ireland or another minor power in hopes of avoiding getting drawn into the titular conflict, but any nation of any size is going to hear the call of “Deus Vult” (or “Jihad”, depending on which side you're on) The geographic scope is also limited to Europe and the Middle East, the major players in the Crusades.
“Crusader Kings 2” (CK2) covers, not surprisingly, the time period of the Crusades.
