Ali ibn Husayn (Arabic: ??? ?? ????) (Approximately: January 6, 659 AD - October 20, 713 AD) [LINK: http://al-islam.org/masoom/bios/4thimam2.html] Ketab Al Irshad, Sheikh Mufid he is the fourth Shi'a Imam. He is the third Imam according to the Isma'ili Faatemi sect. He is the brother of Ali al-Asghar ibn Husayn and Ali al-Akbar ibn Husayn, the son of Husayn ibn Ali and Shahrbanu bint Yazdgerd III, and the great-grandson of Muhammad. He is known as Zayn al-Abidin (Beauty of the Worshippers). He is also known as Imam al-Sajjad (the Prostrating Imam) and Saiyed as-Saajedeena war-Raake'een (Leader of those who prostrate and bow down). Birth and family life Ali ibn Hussayn was born on the 5th of Shabaan 33 AH/654 AD in Medina. His father, Hussayn ibn Ali, was a grandson of Muhammad. Shi'a Muslims believe that Ali ibn Hussayn's mother was Shahrbanu, the daughter of the last Sassanid