The Yoruba are a Central Nigerian tribal group, originally descended from a Hausa migration from the northeast in about 900 AD. A small kingdom – Ile Ife – was founded by Oduduwa, followed by great sociopolitical expansion into Southwest Nigeria, Benin, and Togo. The influence of the city was felt far beyond these boundaries, however, and many smaller political entities were held under its sway. Communities were presided over by the Oba (king) and various senates (Ogboni), and councils made up of guild leaders, merchants and the lesser aristocracy (related to the Oba). The Yoruba have an exceptionally rich and diverse mythology, history and religious context, all of which are directly linked to their artistic output; this grouped heritage is known as the Itan.