How many Nations originally made up Iroquois league?

There were orginally five Nations.

Mohawk Nation - Kanien'kehá:ka - People of the Flint

Oneida Nation - Onayotekaono - People of the Standing Stone

Onondaga Nation - Onöñda'gega' - People of the Hills

Cayuga Nation - Guyohkohnyoh - People of the Great Swamp

Seneca Nation - Onondowahgah - People of the Great Hill