You can easily defeat any infantry from i.e.(Elite Teutonic Knight to Militia) 
using your Arbalests. To accomplish this you must build an archery camp research 
the archer to crossbowman and then to arbalest. These Arbalests when fully 
researched e.g. (Carthaginian Tactics) are extremely powerful in range attack 
and somewhat weak in combat. Just create 15 arbalests, Double-Click any one to 
select all of them and just Right-Click to attack any enemy infantry or cavalry. 
When our men they will come nearer to attack the enemy infantry attack the 
arbalests. Since the arbalests are more in number the enemy infantry will die 
on their way when trying to reach our men. The arbalests have very long range 
so that they can easily kill the infantry and siege units. If they (enemies) 
follow this technique it will be a problem to you so please be quicker. 
If more doubts persists, Mail me.