Uthman remained the Caliph for twelve years. During these twelve years, Uthman presided at the Hajj ceremonies personally for ten years. He could not perform the pilgrimage during the first year of his caliphate, as he was suffering from the oozing of blood from the nose. That year Abdur Rahman b Auf led the Muslims in Hajj on behalf of Uthman. Uthman could not perform the pilgrimage during the last year of his life, as he was besieged in his house by the rebels. On that occasion, Uthman appointed Abdullah b Abbas as the "Amir-ul-Hajj".