ʿAlī b. Abī Ṭālib (Arabic: علي بن أبي طالب) known as Imam ʿAlī (a) (b. 23 BH/600 - d. 40/661) is the first Imam of all the branches of the Shi'a, a companion, a narrator, and a scribe of the Qur'an. He is the fourth caliph of the Rightly Guided Caliphs in Sunni Islam. Ali (a) is the cousin, and son-in-law of the Prophet (s), the husband of Lady Fatima (a), the father of Imam al-Hasan (a) and Imam al-Husayn (a). The rest of the Imams of the Shi'a are his descendants. According to Shi'i historians and many Sunni scholars, he was born inside the Ka'ba. He was also the first Muslim.
Based on evidence from the Qur'an, hadith, and history, the Shi'a believe that 'Ali (a) was the direct designated successor of the Prophet (s). Some verses of the Qur'an point to his infallibility. According to Shiite and some Sunni sources, roughly three-hundred verses of the Qur'an were revealed with regards to his virtues. When the Quraysh plotted to assassinate the Prophet (s), it was 'Ali (a) who slept where the Prophet (s) used to sleep, and thus helped the Prophet (s) to secretly leave for Medina. In the pact of brotherhood in Medina, the Prophet (s) chose 'Ali (a) as his brother. Except for the Battle of Tabuk when he stayed in Medina as the deputy of the Prophet (s), 'Ali (a) was with the Prophet (s) in all the battles. He was the most proud commander of Islam.
After the Prophet's (s) demise, a group of people pledged allegiance with Abu Bakr in Saqifa as the caliph contrary to what the Prophet had explicitly stipulated in Ghadir. 25 years later after the caliphate of Abu Bakr, 'Umar b. al-Khattab and 'Uthman, 'Ali (a) accepted the caliphate at the overwhelming insistence of the Muslims. During his short rule, he was faced with three rebellions and was ultimately assassinated by one of the Kharijites while praying in the Mihrab (the prayer niche) of the Kufa Mosque, and was then secretly buried in Najaf.
Ali (a) is considered as the father of many Islamic sciences including Arabic literature, Islamic theology, jurisprudence, and exegesis. Scholars of different sciences have tried to trace back the chain of their hadiths to him. Nahj al-balagha is a selection of his speeches and letters.
