Among the most sacred objects in Bamana belief is the boli
), a spiritually endowed object which, according to Conrad (in
Colleyn, Bamana: The Art of Existence in Mali, 2001, p. 28) 'receive[s] sacrifices in order to call upon and influence the vital spiritual force known as nyama
can be fashioned of virtually any kind of material including wood, bark, stones, tree roots, leather, metal, cloth, bone, hair, animal tails and claws, and human ingredients including blood, excrement, placentas, and pieces of corpse. [... The] boli
has been described on a cosmological level as both a symbol of the universe and a receptacle of the forces that animate the universe. It is, moreover, an intermediary that permits communication with the ancestor or supernatural power whose force permeates it. [...] As repositories of enormous spiritual power or nyama
are viewed with awe and fear. They were traditionally the most essential instruments of communication between earthly mortals and the supernatural powers that control nyama
, and as such, according to Sarah Brett-Smith, they are an important part of the Bamana judicial structure, inanimate objects to which the Bamana community entrusts its decision making.'
In 1931, Michel Leiris, a member of the Dakar-Djibouti Expedition, described a 'boli du kono', calling it 'one of these bizarre shapes [...] in the form of a pig, always in nougat brown (that is to say congealed blood) that weighs at least fifteen kilos [...]' (Leiris, Mirroir de l'Afrique, 1996 , p. 195). Two years later, in 1933, the same boli appeared in Le Minotaure, having captured the attention of the surrealists and the French intellectuals who contributed to this avant-garde magazine: 'the object was brought to the center of an enthusiasm for Primitivism [...] and it was considered one of the masterpieces of the Musée de l'Homme' (Colleyn, Bamana, 2009, p. 22).