The Bábi Faith (Persian: بابی ها‎ Bábí há ) is a religious movement that flourished in Persia from 1844 to 1852, then lingered on in exile in the Ottoman Empire (especially Cyprus) as well as underground. Its founder was Siyyid `Alí Muhammad Shirazi, who took the title Báb—meaning "Gate"—from a Shi'a theological term. Unlike other Islamic messianic movements, the Bábí movement signalled a break with Islam and attempted to start a new religious system. While the Bábí movement was violently opposed and crushed by the clerical and government establishments in the country in the mid 1850s, the Bábí movement led to the founding of the Bahá'í Faith which sees the religion brought by the Báb as a predecessor to their own religion, and gives a renewed significance to the Bábí movement.

Within Shi'a Islam exists a large group known as the Twelvers who regard the twelfth Imam as the last of the Imams. They contend that the twelfth Imám went into concealment or occultation in 874 AD, at which time communication between the Hidden Imam and the people could only be performed through mediators called Bábs (gates) or Na'ibs (representatives). In 940 AD, the fourth of the representatives claimed that the Hidden Imam had gone into an indefinite "Grand Occultation", and that he would cease to communicate with the people. According to Twelver belief, the Hidden Imam is alive in the world, but in concealment from his enemies, and that he would only emerge shortly before the Day of Judgement. At that time, acting as the Qá'im (He who will arise), also known as the Mahdi (He who is rightly guided), the Hidden Imam would start a holy war against evil, would defeat the unbelievers, and would start a reign of justice.