The Osun-Osogbo festival is a sequence rather than a single day. It opens with Iwopopo, the ritual cleansing of the town, which clears the ground for everything after it. A few days later the sixteen point lamp is lit, the count of sixteen recurring here as it does throughout Yoruba ritual. Then comes Iboriade, at which the crowns of the past Ataojas of Osogbo are brought out and assembled before the reigning Ataoja to be blessed, in the company of the Arugba, the Yeye Osun and the priestesses. The town's dead kings are, in effect, present.
The close is the walk to the water. The Arugba is a young woman of the royal house who carries the covered calabash of offerings on her head from the palace into the grove and down to the Osun river. She is not a priestess and she is not a sacrifice. She is a bearer, and the crowd lining her route casts its troubles onto her path as she passes, so that what she carries out is more than what was put into the calabash. She does not speak on the walk and she does not stop.
Osun herself is the river, and the river is where the town began. The founding account of Osogbo is a bargain with her, in which the settlers were granted the site and the water in exchange for an annual observance. The festival is the keeping of that bargain, renewed every August, which is why it is the town's festival as much as the goddess's.