In the story The Iroquois Constitution The author’s purpose in writing this constitution is to set some laws for the tribes that were part of the Iroquois Confederation to live by. Also the author uses imagery to help the reader picture what the author is describing. When the author is talking about the “Tree of the Great Peace,” you can picture it in your head. The author also uses symbolism. For example, the roots of that tree symbolized peace and strength.