Siyyid Ali Muhammad Shirazi was a young Persian merchant with a reputation for piety when, on the night of 22 May 1844, he told a Shaykhi student named Mulla Husayn that he was the Bab, the Gate to the Hidden Twelfth Imam whose return Twelver Shia Islam had awaited for a thousand years. Mulla Husayn became the first of eighteen disciples the Bab called Letters of the Living, who carried his message across Persia and into Iraq.
Over the following years the Bab's claims grew more radical, moving from Gate of the Imam toward an independent prophetic status, a Manifestation of God in his own right whose revelation superseded the Quran as Muhammad's had superseded earlier scripture. His central work, the Bayan, laid out new laws, including a calendar of nineteen months of nineteen days, and predicted the imminent appearance of a still greater figure, He Whom God Shall Make Manifest. The claims scandalised the Shia clergy, who regarded them as heresy, and the Qajar state, which saw a rapidly growing movement of restless followers. The Bab spent most of his final years imprisoned in remote fortresses, continuing to write and direct followers by letter, while sporadic Babi uprisings hardened both sides. He was tried in Tabriz and executed by firing squad on 9 July 1850, still in his early thirties.