Final answer:
The Iroquois used strings of shells called wampum as a medium for recording important events, formalizing agreements, and as currency. Wampum production increased after European contact allowed for easier bead creation.
Step-by-step explanation:
Strings of shells, specifically referred to as wampum, were a significant aspect of the Iroquois people's material culture. The Iroquois used wampum made from white and purple shell beads for several purposes, including the recording of important events, formalizing agreements, and as currency in their economic system. Wampum was highly valued and, after the 1600s, the Iroquois began manufacturing it more extensively as a medium of exchange.
Wampum served distinct functions such as ceremonial use and jewelry besides its economic role. Following the arrival of European traders, the Iroquois found new materials to work with. Iron awls made it much easier to produce shell beads, leading to an increase in wampum production. The Iroquois incorporated both their traditional art with the influence of European goods, a transformation seen in various aspects of their culture post European contact.