According to the philologist-historian Paul Kraus (1904-1944), Jabir cleverly mixed in his alchemical writings unambiguous references to the Ismaili or Qarmati movement. Kraus wrote, 'Let us first notice that most of the names we find in this list have undeniable affinities with the doctrine of Shi'i Gnosis, especially with the Ismaili system'. Henry Corbin believes that Jabir ibn Hayyan was an Ismaili. Jabir was a natural Philosopher who lived mostly in the 8th century; he was born in Tus, Khorasan, in Persia, well known as Iran then ruled by the Umayyad Caliphate. Jabir in the classical sources has been variously attributed as al-Azdi al-Barigi or al-Kufi or al-Tusi or al-Sufi. There is a difference of opinion as to whether he was a Persian from Khorasan who later went to Kufa or whether he was, as some have suggested, of Syrian origin and later lived in Persia and Iraq. His ethnic background is not clear, but most sources reference him as a Persian. In some sources, he is reported to have been the son of Hayyan al-Azdi, a pharmacist of the Arabian Azd tribe who emigrated from Yemen to Kufa (in present-day Iraq) during the Umayyad Caliphate. while Henry Corbin believes Geber seems to have been a non-Arab client of the 'Azd tribe. Hayyan had supported the Abbasid revolt against the Umayyads, and was sent by them to the province of Khorasan to gather support for their cause. He was eventually caught by the Umayyads and executed. His family fled to Yemen, where Jabir grew up and studied the Quran, mathematics and other subjects. Jabir's father's profession may have contributed greatly to his interest in alchemy.