Answer:
The main purpose of the Iroquois League was to help the tribes unite.
Step-by-step explanation:
The exact date of establishment of the Iroquois League is unknown. Historians have agreed on the period around 1570, in any case this date is before the first contact with Europeans. There is also agreement on the causes that led to the formation of the league: in the 16th century, the relationships between the tribes deteriorated to such an extent that there were endless, cruel wars between them. The Iroquois were at risk of annihilating each other.
The formation of the Iroquois League ended the wars among themselves and gave the Iroquois a time of peace and relative prosperity. The alliance also led to political unification and military power and was an almost insurmountable opponent for tribes outside the League for about 130 years. League members were only obliged among themselves to live in peace. They could wage war against other tribes and pursue their own interests.