I try to be as prepared as possible. I haven't suffered something like that since I was a wee Settler. I built what I had thought was a large stack (~15 marines, 1 artillery, and 1 anti-tank), and attacked Churchill. Me, not understanding combat mechanics, targeted a hill city with a rather large concentration of CG longbows and a massive cultural presence. I attacked all out with my marines. Next turn, Churchy brought a large amount of trebs and maces. There were no survivors.