This article records tradition as it has been passed down and reported. Its sources are not yet part of the atlas's verified catalogue.
On 22 April 1863, Baha'u'llah left the house in Baghdad where he had lived since an earlier exile from Persia, and entered the Najibiyyih garden on the banks of the Tigris. He did not enter it as a private retreat; he entered it as the beginning of a fresh exile the Ottoman authorities had just ordered, one that would carry him further still, toward Constantinople.
Over the twelve days he remained in the garden before that onward journey began, Baha'u'llah declared to the companions gathered around him that he was the one God would make manifest, the figure earlier Babi teaching had long awaited. That declaration, made inside a garden he had entered as an exile rather than chosen as a pulpit, is the founding claim of the Baha'i Faith. He left the Najibiyyih garden on 3 May 1863 to continue the exile the declaration itself had been made under.
What this changed for the Baha'i Faith's spread was the creation of a fixed founding moment the religion could date and return to, even though the moment itself took place under Ottoman order rather than by any choice of timing or venue on Baha'u'llah's part. The garden and the twelve days spent in it are commemorated annually as the festival of Ridvan, the closest thing the faith has to a single point of origin, dated to an exile its founder did not choose rather than to a ministry begun in freedom.