It's all about the terrain
From the perspective of the Romans, you play as Marcus Aurelius, the last of the "Five Good Emperors" who governed the Roman Empire from 96 to 180 (see you've learnt something already!). Following the video footage that introduces you to the campaign I set out on a practice mission, which enables you to get to grip with the control system and user interface. The first mission involved threatening some local farmers into paying their taxes by killing 50 of them until the rest decide to leg-it and pay up, but as you move through the 14 campaign missions and 100 of the most important battles of the time, the action becomes more frantic and the missions become more important in securing the future stability of Rome; the idea is to extend the influence of Rome by winning these battles and capturing regions.
Each battle begins with an introduction to the mission, a run down of the terrain you'll be fighting over, and a few tips on how to use the terrain to your advantage – more about that in a second. Then, you enter the army camp where you can upgrade and recruit new squads (units), buy weapons, and heal wounded soldiers. As you progress through the missions you gain fame and money as the influence of Rome extends. This money can then be spent in your army barracks on recruiting or upgraded these troops. There are 16 units available, ranging from cavalry to heavy infantry, all of which have their own attributes and cost various amount of denari dependant on their strength. For example, at the lower end of the scale you can recruit peasants, who are light infantry and are good at dishing out melee damage, but are weak at ranged combat. If you've got the cash however then you can fork out a few thousand denari on the Trialii, a group of heavy infantry soldiers with high armour counts and high morale. At the beginning of the game there are only a few units available, but as you win battles and gain fame you'll unlock these tougher squads.