hm. let the barbarians come close and then attack them. just always take 1 of your units an klick it to attack another unit, until every enemy unit is attacked by at least one of yours.
if you have superior numbers let your reserves march to the flanks and push into the enemys rear.... while you work on making the enemys flank rout you have to take care of your strong center who sould hold out against the gaesaetae (well, IF they are in the center). Your cavallery goes after the enemys cav.
Just try to roll up the enemys line. Don't chase routing enemys, just go further to the center, till you can attack the gaesaetae with your "free" heavy infantery. Make sure you kill them all. Routing enemys you chase with your cav. or beat them in the next battle when they have no gaesaetae anymore.
If the gaesaetae attack your flank, make sure you have some heavy infantery there to hold out. You attack the enemy, so you choose wich unit fights wich one.
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