Between 1848 and 1852, the Babi community in Iran faced a sustained campaign of violence from both religious and civil authorities, alarmed by the movement's rapid growth and its claim to have superseded core elements of Islamic law. The most significant single episode was the siege of Fort Tabarsi in Mazandaran province, where several hundred Babis, including a number of prominent early followers, held out for months against a much larger government force before being defeated in 1849, with most of the defenders killed either during the fighting or after surrendering under a truce that was not honored.
Further violence followed across several Iranian cities in the years afterward, including further sieges, mob attacks and public executions of Babi believers, often carried out with considerable brutality intended to serve as a deterrent to the wider movement. Iranian clerical authorities, who regarded Babi teaching as a direct heretical challenge to Islamic law, and the Iranian state, increasingly concerned about the movement's scale and its perceived association with unrest, cooperated in varying degrees across different regions to suppress the movement through arrest, exile and execution.
The persecutions culminated in the execution of the Bab himself at Tabriz in July 1850, and continued afterward with a further wave of killings in 1852 following an attempt on the life of the Shah by a small group of Babis acting, according to most accounts, without wider community sanction.