Combat is fairly simple. Ranged strikers get first strikes at +1 attack. Defending units take hits and are removed if HP goes to 0.
After that, all units remaining attack and defend until only one side is left. Order of loss/hits is as follows
Persians: infantry, calvary, immortals, general, then xerxes.
Greeks: greek infantry, spartan infantry, athens general, spartan general, leonidas.
After the battle is over, if there are more than 3 units remaining, they are removed from play. If those units are Persian,
they count towards the Victory Bid.