In 1850, the Bab was charged by Shi’i religious officials with heresy and was put to death by firing squad. Subsequent public protests and mob violence claimed the lives of thousands of his followers. As part of its crackdown on the followers of the Bab, the government incarcerated Baha’u’llah. He was kept in an underground prison in Tehran, which Baha’u’llah describes in his writings as filthy, dark and “foul beyond comparison.” The government released Baha’u’llah in 1853, and exiled him to Baghdad, then part of the Ottoman Empire. It was during this exile that he publicly announced the establishment of the Baha’i faith. Indeed Baha’u’llah claimed to be the manifestation of God that the Bab had foretold and gained a large following.