lmost all the battles you face will take place within your province. Occasionally, Caesar might request the help of your legions in defeating some far-off enemy of Rome; without such instructions from the Emperor, your legions stay within the borders of your province.

hen invaders attack your province, they rapidly assess your military strength and devise a plan of attack. If you have legions, organized enemy armies draw their troops up into formations, then advance against your men. Rabble like Gauls, Celts or Goths just mass into a crowd and charge your legions. Form your defensive lines in the enemy's path quickly, preferably far from the city walls: Your legions exist to prevent enemies from reaching the city.

If you've garrisoned your forts with enough quality soldiers, and you use sensible tactics, you should win the day. Your legions will kill or drive away all the invaders, then return to their forts to replace their losses and restore their strength. Victory in battle improves their morale, making them that much stronger for the next fight.

Should you lose the battle, or some enemy invaders manage to sneak past your lines, your city's walls and towers are the next line of defense. The enemy has to break through while tower guards try to defeat them with javelins and ballista missiles. You are helpless to affect the outcome of this conflict, aside from cheering on your guards.

Once the enemy enters your city, you can order your soldiers to pursue them there, but they will have trouble manoeuvering in formation and will fight less effectively. If you have to order your legions into the city, they've failed in their primary role of keeping the invaders at bay. Remember that wall-guards are highly specialized soldiers, and have strict instructions not to leave their posts under any circumstances .

Even if the invaders defeat your legions and get past your walls, all is not quite lost. Prefects aren't soldiers, and won't meet the enemy in any organized fashion, but neither will they go down without a fight. If your legions and tower guards weakened the enemy enough, city prefects might be able to finish the job.

Some of your other citizens might surprise you, too. Although they have no official responsibility to defend the city, gladiators and lion tamers aren't likely to stand by helplessly while barbarians destroy their homes and businesses.

Everyone else is unarmed and defenseless. Most citizens try to get away from invaders. Those who can't – well, their best hope is to die quickly.

All invaders have their own objectives; it might be food, money, the death of your people, or simply wanton destruction. Granaries, warehouses and the senate building are frequently prime targets. The destruction these enemies can inflict is horrible, possibly enough to level your city and maybe even spell the end of your career. Prevent street fighting at all costs!

Your builders are not keen to work during or close to a battle. When enemy soldiers are in your province, immigrants wisely avoid your city.