Muhammad ibn Ali ibn Abdallah
Muḥammad ibn ʿAlī ibn ʿAbd Allāh ibn ʿal-ʿAbbās or Muḥammad al-Imām was the father of the two first 'Abbâsid caliphs, Al-Saffah and Al-Mansur, and as such was the progenitor of the Abbasid dynasty.
He was the son of Ali ibn Abd Allah ibn al-Abbas and great-grandson of al-‘Abbas ibn ‘Abd al-Muttalib, the uncle of the Islamic prophet, Muhammad.
Abbasid Da'wa
Muhammad ibn Ali was the leader of the Abbasid da'wa during the Umayyad Caliphate. He was informed by Abu Hashim that the Caliphate would belong to the Ahl al-Bayt, and he began the mission accordingly. After his death, his son Ibrahim ibn Muhammad succeeded him, but when the last Umayyad caliph Marwan ibn Muhammad learned of his status and location, he had him arrested and imprisoned, where he eventually died. He was succeeded by his brother Abu al-Abbas al-Saffah, who openly proclaimed the da'wa for the first time, established the Abbasid Caliphate, and seized the Caliphate.Muhammad ibn Ali was a pious and scholarly man. He was likely born in the village of Humayma in Jordan and dedicated himself to religious study and devotion. In Humayma, he owned about five hundred trees, under each of which he would pray two rak'ahs. He taught his sons both knowledge and worship. He bore the title "al-Sajjad", which distinguished him from Ali Zayn al-Abidin. He was fourteen and a half years younger than his father, and people often could not distinguish between him and his father until he dyed his beard with henna while his father dyed his black.