‘Alī ibn Ḥusayn (Arabic: علي بن حسين زين العابدين) (approximately 6 January 659 - 20 October 712)[2] is a great-grandson of Muhammad as well as the fourth Shī‘ah Imām (the third Imām according to the Ṭayyibī [Bohra] Ismā‘ilī). His mother was Shahrbānū and his father was Ḥusayn ibn ‘Alī. His brothers include ‘Alī al-Aṣghar ibn Ḥusayn and ‘Alī al-Akbar ibn Ḥusayn. He is known as Zayn al-Abidīn "Beauty/Best of the Worshippers". He is also referred to as Imām al-Sajjad "the Prostrating Imām" and Sayyid as-Sājjadīna wa r-Rāki‘īn "Leader of Those who Prostrate and Bow".