Try to put your cav in one big group (so they overlap eachother)and then charge, break off, recharge etc in the rear. While you are doing this, you can attack them from the front too with urbans, to make them feel surrounded as wartrain said, or you can wait for them to turn to fight the cavalry (if they don't, the better for you) and then charge their rear again with your urbans. Also remamber to trow all your pila before charging if you can, this can decimate them alot. If you can pull it off, it might also be very efective to use urbans in the same role as you usualy do with the cav: get urbans instead of cav, place extra urbans on the flanks, beat the enemy cav (thats the tricky part, if the enemy don't want to engage, they can just run away) then circle around and charge their rear with urbans instead. On impact, they will probably not make as much damage as the praetorian cav, but since there are more of them and they have better melee stats, they should be able to do more damage in the long run. Again, if the enemy turns, charge their rear again. If they don't, keep on attacking the most vulnerable part of a phalanx, and kill them.
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