My win rate on Emperor is close to 100%, so I decided to try Immortal. Settings: Small map, standard speed, 6 civs pangea, random leader. It was mid way through the game and I had captured 2 capitals. There were three AI civs remaining. Germany and I (England) were at war with the Iroquis. In order for Iroquis to make it into my territory it would have to pass Germany first. Germany and I were behind in tech with our strongest units being crossbowman and longswords, while the other AIs had rifles already. I massed all my troops in Germany's territory so that we could stop the Iroquis invasion. The Iroquis, while having a tech lead, couldn't make a dent on our defenses. Having longbowman was a good advantage too. I thought I could keep this up indefinitely. After a couple of turns of my longbowmen killing the Iroquis forces, a message pops up that my worker near MY capital has been captured. I think to myself, "WTF? How did the Iroquis get there? My capital is in the corner of the pangea map and so it couldn't be the Iroquis... I scan back to my capital and see a couple of rifleman approaching. My capital is completely defenseless with all my units in German territory. While I was busy concentrating my forces on one side of the map, the Iroquis bought off a city state right next to my capital. The rifleman of the Iroquis' newly aquired ally approaching my capital had nothing but empty space to go through. I didn't have enough gold to rush buy either. I decided to give up this match and I felt I made a big mistake here. I had never seen such a tactic on Emperor.