I once went to byzantium as parthia in RTR 5.4, i took it and the macedonians sent army after army, i couldn't recruit new troops, all i had was a load of auxiliary troops that i started with, i must have defeated about 7 full enemy armys when the dacians joined in, sending their own troops to attack Byzantium. I fought army after army of enemy, my army ended up mega elite, but every battle i lost a few more men, i finally ran out of troops i only had one unit left. (then finally i finished a stables and was able to build reinforcements).