Ogboni is described in the scholarship as having developed alongside Oyo's own political institutions rather than being founded by a named person at a datable moment, and no Yoruba historical or oral source names a founder.
What would resolve this Oyo court-history research or archaeology tying Ogboni's earth-veneration role and its check on royal power to an identifiable stage of Oyo's own political consolidation.
OpenYoruba political history and religious anthropologyPeter Morton-Williams, The Yoruba Ogboni Cult in Oyo