Symbolism, Imagery, Allegory
Even though slavery is over by the time the play begins, its legacy looms large. There is still a ton of tension between the British occupiers and the Yoruba (be sure to check out our thoughts on leftovers elsewhere in this section for a bit more on this), and there are multiple references to slavery. It's not exactly front and center as a topic, but it's definitely always there in the background.
However, we really start thinking about slavery a lot when Elesin gets locked up—by white men—for trying to carry off the suicide ritual. Just to make sure the symbolic power of having Elesin in chains isn't lost on us, Soyinka has Pilkings select a prison that is directly tied to the legacy of slavery.
When Elesin is first captured, Pilkings takes the aide-de-camp Bob aside and arranges for Elesin to be locked up in the "cellar in the disused annex of the Residency […] where the slaves were stored before being taken down to the coast" (4.175). A clear line is drawn, then, between the stopping of the ritual and the systemic enslavement of the Yoruban people. And what do they both have in common? Oppression: They are both ways of laying claim to Yoruban lives.
Then, to take the symbolism even further and make it even more tragic, Elesin ends up strangling himself with his own chains when he sees that his son, Olunde, has sacrificed himself in his father's place. In other words, Elesin fails to kill himself according to Yoruban tradition, and instead falls prey to practices—and actual tools—of white oppression. It is anything but an honorable death, and the fact that he uses his captors' shackles to pull it off perfectly symbolizes the British role in that dishonorable outcome.