I would not split our forces, until after Berlin and any other walled city is captured. In my opinion, we need 10 Catapults to take down Berlin's walls from 50% to about 12% defense in a single turn. A longer siege will allow Frederick to sent more. military units to Berlin. At the very least, all Catapults must go to Berlin. Six HAs could go to Berlin and four promoted HAs can go to a 20% defense city. I don't like even this split. Caveat: Well, maybe splitting our stack at Monarch level is reasonable. I play almost exclusively Deity level, so my suggestions might be too conservative for Monarch level AIs.