Alright, little clarification here.
Before you start a campaign, a downward sword pointing into a province on the starting map indicates that you must own that province, in the overall number of provinces you must own before the year 476 rolls around.
Meanwhile, two crossed swords on the campaign map in the game indicates a famous battle, whereas the battle must have been an overwhelming heroic victory. The year, and two commanders name's are recorded on the little thing. Just a nice little reminder of a good (or poor) job on someone's part.
Nations to play in MIITW:
Holy Roman Empire
Poland