A number of theories have been proposed regarding Avicenna's madhab (school of thought within Islamic jurisprudence). Medieval historian Ẓahīr al-dīn al-Bayhaqī (d. 1169) considered Avicenna to be a follower of the Brethren of Purity. On the other hand, Dimitri Gutas along with Aisha Khan and Jules J. Janssens demonstrated that Avicenna was a Sunni Hanafi. However, the 14th cenutry Shia faqih Nurullah Shushtari according to Seyyed Hossein Nasr, maintained that he was most likely a Twelver Shia. Conversely, Sharaf Khorasani, citing a rejection of an invitation of the Sunni Governor Sultan Mahmoud Ghazanavi by Avicenna to his court, believes that Avicenna was an Ismaili. Similar disagreements exist on the background of Avicenna's family, whereas some writers considered them Sunni, some more recent writers contested that they were Shia. COUNT 5
QSN1 What secret society was Avicenna considered to be a follower of? ANS1 the Brethren of Purity QSN2 Who thought that Avicenna was a Brethren of Purity follower? ANS2 Medieval historian Ẓahīr al-dīn al-Bayhaqī QSN3 What Islamic denomination was Avicenna thought to be a member of? ANS3 Sunni QSN4 Who thought Avicenna was a Shia? ANS4 Nurullah Shushtari QSN5 What was the name of one man who thought Avicenna was Sunni? ANS5 Jules J. Janssens