Troop types in Field of Glory can differ widely in quality. Elite troops such as Roman Triarii, Macedonian Agema or Persian Guard cavaly would be much more effective at fighting (reflecting their better training, protection, skill etc.) than a levied foot soldier or typical Gallic warrior.
This difference in quality is reflected in re-rolling dice (shown in the rules where 'quality re-rolls apply'). This allows the opportunity for that quality difference to be shown on the field.
So the following rules apply
Elite troops can re-roll 1's and 2's.
Superior troops can re-roll 1's
Poor troops must re-roll 6's.
Dice re-rolls
A dice can only be re-rolled once. So if a Superior troop type rolls a 1 and then re-rolls for 1 again, that dice cannot be re-rolled - the result stands.
Similarly if a Poor BG throws a 6 and re-rolled another 6, the result stands.
If a battle line is of mixed quality troops needs to re-roll, it re-rolls for the worst quality Battle Group in the line. So a mix of Superior and Average troops would NOT re-roll 1's. A mix of Average and Poor troops WOULD re-roll 6's.
Note that a re-roll can never be taken as less than the previous result. So if an Elite BG rolled a 6 and 2 then re-rolled the 2 to get a 1, the 1 would actually be counted as a 2.
Commander in the front rank
This represents the impact on troops on seeing their commander fighting alongside them - raising morale and the effort put into winning. The Commander temporarily upgrades the quality ONLY of the BG he is attached to (so he does NOT raise the quality of other BG's fighting alongside).
In addition, he can only influence the CMT's or cohesion tests of the BG he is with. He can have no influence over other BG's in his command range.
Similarly he only raises the quality of the BG if he is fighting in the front rank. If attached to the side or rear he does NOT influence quality re-rolls.
Therefore if fighting in the front rank, the commanders base must (if possible) be placed on the front rank (displacing troop bases to its rear if necessary) and the player must declare when this is being done. The declaration takes place BEFORE any close action dice are thrown.
The quality of troops is raised by one level - so Average roll as Superior (and so re-roll 1's), Superior roll as Elites (re-roll 1's and 2's) and Elites re-roll on a 1,2 and 3.
In addition, the Commander - once committed to fighting in the front rank - cannot influence cohesion tests, complex move tests or any other activity (except for bolstering the BG he is attached to) until the BG is no longer in close combat OR in contact with enemy routers. Note that if the BG with which the commander is fighting is foot in combat with cavalry, then when the cavalry Break Off the BG is no longer in close combat so the commander can move away from the BG in the Joint Action Phase.
There is the potential to lose a commander if fighting in the front rank. If the BG to which he is attached suffers a total of 2 or more hits in close combat, the opposing player rolls 2 dice (no re-rolls).
If the commanders's BG lost the close combat, then the commander is killed on an 11 or 12.
If the commander's BG won the close combat (but still took 2 hits or more) he is killed on a 12.
The lost commander is removed from play and the units he displaced are replaced in their original position BEFORE measuring to see if any friendly BG's are in range to test cohesion for seeing him lost. Note that the commander must be in line of command to force a test.
This is often overlooked. If we take (for example) a Persian army using mercenary troops - those troops need their own commander who can only influence the activities of these troops themselves (so a mercenary commander cannot command Persian troops or influence their cohesion tests, CMT's etc.). If a mercenary unit loses their commander, nearby Persian troops DO NOT need to test as he is not in their line of command. Darius getting killed is a different matter!
If lost, replace the troops he displaced THEN measure upto 3MU's from the BG in all directions to see which BG's may need to make a cohesion test.