kill the senate, they are greedy, ignorant, selfish dogs. kill them and rape thier sheep.
all you need is some archers, a couple of strong cohorts and some mercenary hoplites. the heavy siege weapons are not needed to defeat the senates gold army but they help. just north west of rome is a river that has severval crossings. leave your army on the bridge and wait to defend. hoplites and legionaries right up at the bridge with projectiles covering the sides will hold anything they can throw at you if you control your archers well. almost all infantry holds shields on the left arm, so from an advancing army's right flank is where projectiles will do the damage.