Why dont you get prestige after winning a war ?

Could anyone please explain why you sometimes dont get any prestige after winning a war ?
Example:
i go to war with 20.000 cavs against 2400 cavs i win and i cured 6% 100 cavs he cures 8% 202 cavs and he convinced 8% i also took down some level 10 turrets.
He left 202 cavs.
Is it because of turrets or curing is higher or convince skill ?
Thanks

Its possible his level is lower than yours and if you attack someone with a lower level, and you loose troops there prestige gain is higher than normal.

their level might be alot lower than you, and maybe you lost too much troops to be counted

[Backburner]

What's your level and what's his level? Level penalty gets huge when you get higher up, that's why I don't use pure cavs to attack at high level.

Im lvl 15 and the defender is lvl 14

[Backburner]

How many did you lose in total? you never actually say how much you and he both lost.

Put it this way, he has level 10 turrets and at a lower level than you, there was no point in killing 2k of his cavs in the first place, you won't earn prestige due to the amount you will lose to his defenses.