It was the place where leaders were chosen when the castes fought for dominance over each other. The opposing leaders would walk into the Starfire Wheel and the ceiling would open, focusing an intense beam of light down on them. Whoever remained long enough to be vaporized, sacrificing their life, would earn the right for their caste to lead.
After Valen formed the Grey Council and established a lasting balance in Minbari society, Varenni was little more than a relic, though like many ancient places on Minbar it was carefully preserved through the centuries. In 2261, The Starfire Wheel was used again at the conclusion of the Minbari Civil War, with the sacrifice of Alyt Neroon leading to the reformation of the Grey Council.