No trade, no population to tax, no money from farming, no big cities to loot; you'll have to live of the mines for which you'll don't have the money to build. Your army is first of all composed of unarmoured spearmen (only a little better than Pantodapoi) and foot archers. Both will suffer heavy casualties in each battle, but you neither have the money nor the population to replace them each time.

Once you are out of the worst poblems, AS will throw the first wave of heavy pikemen at you....