received his mission as a manifestation of God, the Promised One heralded by the Báb. Bahá’ís view this dawning of Bahá’u'lláh’s spiritual mission as the beginning of fulfillment of the Báb’s prophecies regarding "Him whom God shall make manifest". The "inseparable" nature and unity of the twin revelations of the Báb and Bahá’u’lláh are why Bahá’ís consider both faiths as forming one complete religious entity, and the reason the 1844 declaration of the Báb is considered the starting date of the Bahá’í Faith. Banishment from Persia When it was proven beyond any doubt that Baháʼu'lláh was innocent of involvement with the attempt against the Shah’s life, the king finally agreed to free him but decreed Baháʼu'lláh would be forever banished from Persia. Dispossessed of his extensive properties and wealth, in the exceptionally severe winter of January 1853 Baháʼu'lláh with family members undertook a three-month journey to Baghdad, thus beginning what became exile for the rest of his life in territories of the Ottoman Empire. Life in exile Baghdad Upon settling in Baghdad, Baháʼu'lláh began dispatching communications and teachers to encourage and revive flagging spirits of persecuted followers of the Báb in Persia. Over time, a number of Bábís moved to Baghdad to be close to Bahá’u’lláh. One of these was Mirza Yahya, later known as Subh-i-Azal, a half-brother 13 years younger than Bahá’u’lláh, who followed him into the Bábí Faith and even accompanied him on some early journeys on its behalf. After their father's death, Yahya’s education and care were largely overseen by Bahá’u’lláh. During Baha’u’llah’s imprisonment in the Síyáh-Chál Yahya went into hiding, but after Bahá’u’lláh’s exile to Iraq Yahya left Iran in disguise and made his way to Baghdad. For a time Yahya served as Bahá’u’lláh’s secretary in Baghdad, but envy for the growing admiration Bábís showed Bahá’u’lláh led Yahya to seek leadership of the Bábí religion. Attempting to elevate himself among Bábís, Yahya and a few supporters referenced a letter the Báb had written a few years earlier when Yahya was still a teenager, naming Yahya to nominal leadership pending the appearance of "Him whom God shall make manifest". Yahya claimed the letter meant he was actually appointed the successor or vicegerent of the Báb. Knowledgeable Bábís promptly rejected Yahya’s bold claim, because the referenced letter indicated no such status, and due to the fact that other writings of the Báb specifically "eliminated the institution of successorship,