If your main line won't hold head-to-head against the enemy, then holding the flanks doesn't matter.

If your main line can defeat the enemy straight on, and you are only vulnerable to a flanking manuever, then one option is to use cheap, large units in an attempt to slow down the flanking. RTW fights seem to be decided relatively quickly and if you can simply impede the flanking attack then you might have time to win the center and turn to face the flank.

Alternatively, use a Phalanx facing the flank to hold and then use the light fast cavalry to flank the flankers. Even if your flank falls it will take time and the residual flankers will be greatly reduced.

Positioning is also important - if you chase cav with inf you won't be successful often. Place anti-flankers close in behind the line close to the end of the line (as opposed to further out on the flanks) and let the enemy flankers try to make a move then block. But don't go chasing.



ichi