[2] Qasim came to be recognized as one of the chief authorities of the Zaydi school of Shi'a Islam, and was honoured with the titles "Star of the Family of the Prophet of God" (Najm Āl Rasūl Allāh) and "Interpreter of the Faith" (Turjumān al-Dīn).
[3] His brother Muhammad, known as Ibn Tabataba, was recognized as imam, and raised a failed rebellion against the Abbasid Caliphate at Kufa in 814.
[5] Instead, after coming under suspicion from the Abbasid authorities, in c. 827 he moved his family from Egypt to a village (likely modern al-Dur or Dur Abi al-Qasim, some 57 kilometres (35 mi) southwest of Medina) near the wadi al-Rass, whence he received his nisba of "al-Rassi".
[9] He rejected the first three Rashidun caliphs as illegitimate, and held Ali ibn Abi Talib as the only legitimate successor of Muhammad.
[9] His doctrines became the foundation for the religious and legal systems of the Zaydi states in Tabaristan and Yemen, but were heavily amended by his grandson Yahya to a more mainstream Shi'a and Mu'tazilite direction.