Shaykh Ahmad’s doctrines prepared the way...

The sense of messianic anticipation within Shi‘ism was intensified by the spread of the doctrines of the Shaykhi School, named for Shaykh Ahmad al-Ahsa’i (1753-1826). He advanced a metaphorical interpretation of certain traditional tenets of Islam, claiming that the Hidden Imam existed not on earth but in a spiritual realm where he guided the faithful through a ‘perfect Shi‘i’ who was a ‘gate’ to the Imam. Shaykh Ahmad’s doctrines prepared the way for the widespread response within the Shi‘i community, particularly the Shaykhis, to the appearance of the Bab.

(Baha’is of Iran, Transcaspia and the Caucasus, The Volume 1: Letters of Russian Officers and Officials, Volume 1)