How does leadership of mixed nationalities work?
For example, Hannibal has a trait that allows leadership of Spanish, Celtic, Italian, and African units. Does this mean units in his stack will not suffer a penalty for non national leadership?
What about combining a leader with a unit of a different nation? Will a mixed combined unit suffer a penalty?
Say I had Hanno, a Carthaginian, combined with a Spanish unit in a stack under Hannibal. Would Hanno's unit have a penalty or would Hannibal's special trait override it?
And what is the penalty?
In short, I'm very confused as to how this all works. Help!