Dekanawidah is regarded as the author of the Great Law of the Iroquois Confederacy that bound together five Indian Nations, probably early in the late Fifteenth or early Sixteenth Century. A somewhat similar Huron Confederacy is believed to have been instituted in 1450. The Iroquois Great Law replaced cycles of murder, revenge, and violent destruction of villages with a system of justice administered by hereditary chiefs. It is one of the earliest North American constitutions of which we have some knowledge, having been passed down orally with the mnemonic aid of shell-bead patterns, or wampum.

The names of the five nations—Mohawks, Oneidas, Onondagas, Cayugas, and Senecas—were recorded by the first European explorers early in the Seventeenth Century. However, it was not until the Eighteenth Century that the legends of the formation of the Confederacy began to be written down. The process continued, with variations and successive elaboration, into the early Twentieth Century.