Why did the Iroquois League succeed?

Answer 1

When they took captives, they would torture them by cutting off their noses and ears and make them eat both body parts, as well as make them bite of their own fingers. If the captive made a big deal and cried about it, the Iroquois would just kill them. If the captive remained calm and "strong", or took it like a man, the tribe would eat that captive. They believed eating a "manly" or strong man would make them stronger. You are what you eat, so to speak. The women of the tribe would also choose when to go to war, as they were the kin keepers. I think this makes a group stronger, too, lol.

Answer 2

because they managed to keep peace between the nations through the laws the nations made with their council.