In Rome Total War, you basically needed a distration for the enemy to charge at, then cavalry could route... well, everything I encountered. Personal bodyguard units with 20ish cavalry were getting literally hundreds of kills/battle, and did not always lose a single man. [On the other hand, if I only had light infantry, and neglected them a second, half of them died. [That is, the enemies caught up with them.] Otherwise, since I sucked at remembering to build more units, my heavily outnumbered heavy infantry would blunt the first charge, flee, and by then my lighter ranged units were running around, splitting up their forces, and taking a toll on their forces. And cavalry were running down their formations from behind. Tip: A single phalanx of infantry is USELESS against a faster unit of cavalry... and an AI that parades its spear phalanx one way toward my archers, then turns around and heads for my skirmishers, and turns back, etc, is not the greatest of tacticians.