The Longhouse Religion is the popular name of the religious movement also known as the Code of Handsome Lake or Gaihwi:io/Kaliwihyo (Good Message), founded in 1797/1799 by the Seneca prophet Handsome Lake (Sganyodaiyoˀ). This movement combines and reinterprets elements of traditional Iroquois religious beliefs with elements adopted from Christianity, primarily from the Quakers. Anthropologist Anthony F. C. Wallace reported that the Gaihwi:io had about 5,000 practicing members as of 1969.[1]: 3 Originally the Gaihwi:io was known as the "new religion" in opposition to the prevailing animistic beliefs, but has since become known as the "Old Way" in opposition to Christianity.
Prior to the adoption of the single-family dwelling, Iroquois lived in large, extended-family homes also known as longhouses which also served as meeting places, town halls, theaters, and sites for religious ceremonies. Gaihwi:io keeps the longhouses for ceremonial purposes, and the movement was therefore termed the "Longhouse Religion".