You can deal with Centurions by using priests or archers with other units in front of them.
You can beat them if you have enough swordsmen (legions) especially if they are Roman or Choson. They should have 13+7 attack from storage pit to be effective. Any units that have 15 attack or less will only deal 1 damage to centurions per hit as centurions have up to 14 melee armour.
Beware of Macedonian centurions as they are 4x as conversion resistant and have +3 more pierce armour, which makes them very tough. They don’t have the Greek bonuses however. Try balista/helepolis and again you can still use melee and archer combo, but your archers will be limited to horse and elephant archers to be effective (Mace centurions have up to 5 pierce armour).
Of course you can also deal with centurions by using centurions
Throw in some cavalry or attack archer group to deal with siege that will likely also come from Greek AI.