In August 1852 a small group of Babis, acting on their own after the execution of the Bab and the crushing of their movement, attempted to shoot the shah as he rode out of Tehran. The reprisal was indiscriminate and public, and dozens of Babis were killed in the city in ways deliberately made spectacular. Among those arrested was Mirza Husayn Ali, later known as Bahaullah, a nobleman's son who had joined the movement, and he was held in an underground reservoir converted to a prison, the Siyah Chal, chained by the neck in the dark for four months.
Bahai accounts date the beginning of his mission to that confinement, describing an intimation there of the revelation he would announce ten years later in Baghdad. He was released and exiled, and the religion that developed from the Babi movement under his leadership has spread to most countries in the world.
Its position in the country of its origin has never been secure. Bahais are not among the recognised religious minorities of the Iranian constitution, which names Christians, Jews and Zoroastrians and reserves parliamentary seats for them. Since 1979 Bahais have been excluded from higher education and public employment, their national leadership has been imprisoned or executed, cemeteries have been damaged, and the community organises schooling informally in response. United Nations human rights reporting on Iran has documented the pattern repeatedly.