Abu Abdallah al-Shi'i was born al-Husayn ibn Ahmad ibn Muhammad ibn Zakariyya at Kufa in Iraq. Together with his older brother Abu'l-Abbas Muhammad, he joined the Isma'ili missionary network (daʿwa) in the city around 891.[1] According to the eastern Arabic sources, they were recruited by none other than Hamdan Qarmat, the leader of the daʿwa at Kufa, who soon sent the brothers on mission to Egypt.[1]