Husayn received a letter which appeared to have been written by Siyyid Kázim before his death; while his companions assumed that the letter contained an appointment from Siyyid Kázim naming Mullá Husayn as his successor, it contained only veiled instructions for the coming journey. Mullá Husayn is reported to have publicly burst into tears upon reading the posthumous instructions of Siyyid Kázim and realizing the enormity and uncertainty to his task. After celebrating the Muslim holiday of Mawlid, marking the completion of forty days spent at the Great Mosque of Kufa, Mullá Husayn and his companions visited the Tomb of the Imam Ali in Najaf and proceeded toward Búshihr, on the Persian Gulf. After some time there, at Mullá Husayn's urging, they continued to Shiraz in the Province of Fars. At this point they had traveled on foot for approximately 600 miles with no clear intended destination and no guide for their journey except Siyyid Kázim's dying advice to Mullá Husayn. Upon their arrival in Shiraz, Mullá Husayn instructed his companions to proceed to the Vakil Mosque where he would join them for evening prayers. Conversion to Bábism (1844) In Shiraz, on 22 May 1844, he encountered Sayyed ʿAli Muhammad Shirāzi, the Báb, who invited Mullá Husayn to his home. On that night Mullá Husayn told him that he was searching for the Promised Mahdi and shared with him some of the characteristics expected of the Mahdi which he had learned from Siyyid Kázim. The Báb declared that he manifested all of the characteristics of the Mahdi. Mullá Husayn remained uncertain until the Báb had replied satisfactorily to all of Mullá Husayn's questions and had written in his presence, with extreme rapidity, a long commentary on the Surah of Joseph, which has come to be known as the Qayyúmu'l-Asmáʼ ("Maintainer of the Divine Names") and is considered the Báb's first revealed work. Siyyid Kázim had apparently—when requested by Mullá Husayn to do so himself—predicted that the Mahdi would reveal, unasked, a commentary on this Surah. Nabil's Narrative records Mullá Husayn's account of the signs he had been given by the dying Siyyid Kázim to recognize the Mahdi and indicates that Mullá Husayn was quickly convinced that the Báb satisfied these conditions. While the Báb had already revealed his religious mission to his wife, Khadíjih-Bagum and his household servant, Mubarak about a month previous, Mullá Husayn became the first person to