The Bab, the title means the Gate, was Siyyid Ali-Muhammad Shirazi (1819-1850), a young merchant of Shiraz who, in May 1844, declared to his first disciple that he was the bearer of a new revelation from God. Baha'is date the beginning of their era, and of the Baha'i calendar, from that night. For Baha'is he is not merely a forerunner but an independent Manifestation of God in his own right, whose distinct mission was to prepare the way for one greater to come after him.
His claim resonated powerfully with currents of Shia expectation of the Qa'im or Mahdi, the awaited one of the house of the Prophet, and within a few years the Babi movement had spread across Persia and gathered tens of thousands of followers. His earliest disciples, eighteen in number, are honoured as the Letters of the Living; among them was the poet and reformer Tahirih, who became a celebrated advocate of the new faith and of the emancipation of women.
The rapid growth alarmed both the Shia clergy and the state, and the movement met with mounting and ferocious persecution, culminating in armed sieges of Babi communities and mass killings.