I tried this same game in private, did OK until 1700 or so, when the AIs had upped their production enough to be able to send CONTINOUS stacks of 8 units at me EVERY TURN. Even though I had grenadiers to their macemen I could not do what I had to win, which was not just hold my city but hold my developed tiles. 3 grens on a zero-defense tile holding a farm are toast to 5 jumobs and 3 macemen two turns in a row. The only way this would have been possible is if I was able to get infantry by then. Very doubtful since you can't really hold cottages early on due to pillaging. THe AI was very smart and kept varying from which direction they attacked, forcing me to scramble my units around. Again, the ONLY way this can be won in such a configuration is with an ENORMOUS tech lead.