Crusaders win at the Battle of Nicopolis?

[PuffyClouds]

Now, how would Sigismund convince his allies to behave reasonably instead of idiotically, is a completely different issue that involves cultural background and some other factors. IMO, the task was almost doomed unless the leader had an overwhelming authority, which was not the case.

The Popes go on Crusades with the armies to promote discipline.

 

[Aluma]

The Popes go on Crusades with the armies to promote discipline.

The Pope:
*Tells the french to behave*
The french:
Have you ever thought about visiting Avignon?

 

[PuffyClouds]

The Pope:
*Tells the french to behave*
The french:
Have you ever thought about visiting Avignon?

Perhaps a few martyred Popes wouldn't be the worst thing for the institution.

 

[material_boy]

how would Sigismund convince his allies to behave reasonably instead of idiotically

This would require them to not be HYW-era Frenchmen