Some achievements are very difficult to obtain and cannot be consciously completed...they just happen eventually with a certain probability. The achievements of losing against a high-chance Legion and winning against a low-chance Legion just happen over time and require some luck/bad luck.
For the "Master Strategist" achievement, which requires winning a battle against the Romans with a low chance of winning, the chance of winning must be 4% or less. To achieve this, a good recommendation is to take an Egyptian worker to 0 power, equip it with a normal spear, and then attack a 20 power patrol (in Alexandria) with that worker. After a few to many attempts with this method, you should be able to complete the success. See also: [[Tips_for_Quest_Tips for Quest "Master_StrategistMaster Strategist"]]
==Unavailable Achievements==