What I think think the focuse should be know is: , as stated before, the possibilty to have things that happened historically close to the start date being able to happen, while keeping it dynamic, model the trasition between feudalization and centralization and how cultures and melting pots will be handled. Personally I think that what happened with celts and christianity in Britain and the situation in France with the Franks and the schism and conversion of germanic pagans to christendom are also important events during this timeframe.