ʻAbd Allāh ibn Sabaʼ, active 7th century

ʿAbd Allāh ibn Sabāʾ al-Ḥimyarī (Arabic: عبد الله بن سبأ الحميري), sometimes also called Ibn Sabāʾ, Ibn al-Sawdāʾ, or Ibn Wahb, was a 7th-century figure in Islamic history associated with a group of followers called the Sabaʾiyya (سبئية). According to Sunni and Shia tradition, Abd Allah ibn Saba' was a Yemenite Jew from the Arab Himyar tribe who converted to Islam during Uthman's reign. Because of his exaggerated reverence for Ali, he is traditionally considered as the first of the ghulāt. In accounts collected by Sayf ibn Umar, Ibn Saba' and his followers, the Saba'iyya, are said to be the ones who enticed the Egyptians against Uthman and were responsible for breaking the near-settlement at the Battle of the Camel. Modern historians differed on the historicity of Ibn Saba'. Some believe that Abd Allah ibn Saba' and Ibn al-Sawdāʾ should be considered as two separate individuals (Hodgson). Some have described him as semi-legendary or legendary (Taha Hussein, Bernard Lewis, Wilferd Madelung, Leone Caetani, and Shia historians). Others such as Israel Friedlander, Sabatino Moscati, and Sunni historians affirm his existence. His Jewish origin has also been contested. Some modern historians assert that Sayf ibn Umar fabricated the episode about the killing of Uthman to "exonerate the people of Medina from participation in the caliph's murder" and the movement to support Ali as a successor to Muhammad did not exist in the time of Uthman. With the exception of Taha Hussein, most modern Sunni writers affirm the existence of Ibn Saba'.