By the end of the eighteenth century the Haudenosaunee had lost most of their territory, had been divided by the American Revolution, and were confined to reservations on both sides of a new international border. In 1799 a Seneca named Handsome Lake, Ganiodaiio, fell gravely ill and reported a series of visions in which messengers gave him instructions for his people. What he taught over the following sixteen years became the Gaiwiio, the Good Message, and it addressed alcohol, witchcraft, family obligation and the keeping of the ceremonial calendar, combining older practice with elements that had reached him from Quaker missionaries. It is recited by trained speakers at longhouses on a fixed cycle, and the Longhouse religion built on it is practised today across Haudenosaunee communities, alongside Christianity and alongside those who follow neither. It is one of the clearest cases anywhere of a prophetic movement arising in response to colonial catastrophe and becoming a durable institution rather than a moment.
The atlas notes that its ceremonies belong to the communities that hold them, and describes the movement's history rather than its ritual content. The confederacy also continues to assert its own sovereignty, issuing its own passports and refusing at intervals to be treated as a domestic population of either state its territory now crosses, which is a political position with a religious constitution behind it.