Dhūl-Nūn Abū l-Fayḍ Thawbān b. Ibrāhīm al-Miṣrī (; d. Giza, in 245/859 or 248/862), often referred to as Dhūl-Nūn al-Miṣrī or Zūl-Nūn al-Miṣrī for short, was an early Egyptian Muslim mystic and ascetic. His surname "al Misri" means "The Egyptian". He was born in Upper Egypt in 796, Dhul-Nun is said to have made some study of the scholastic disciplines of alchemy, medicine, and Greek philosophy in his early life, before coming under the mentorship of the mystic Saʿdūn of Cairo, who is described in traditional accounts of Dhul-Nun's life as both "his teacher and spiritual director." Celebrated for his legendary wisdom both in his own life and by later Islamic thinkers, Dhul-Nun has been venerated in traditional Sunni Islam as one of the greatest saints of the early era of Sufism. Name It has been speculated by scholars whether "Dhul-Nun" was an honorific (laqab) for the mystic rather than his name proper, which is sometimes believed to be Thawbān. As "Dhul-Nun," literally meaning "the one of the fish [or whale]," is another name for the Hebrew prophet Jonah in Islamic tradition, it is sometimes believed that this title was given to Dhul-Nun in commemoration of Jonah. Life Dhul-Nun is one of the most prominent saints of early Islamic tradition, appearing "in the earliest accounts of Ṣūfism as the leading figure of his generation." Often depicted as the spiritual master of Sahl al-Tustari (c. 818–896), the traditional hagiographies relate that the latter refused to engage in mystical discourse until after Dhul-Nun's death, on account of his recognition of Dhul-Nun's elevated rank in wisdom and gnosis. Dhul-Nun al-Misri is considered among the most prominent saints of early Sufism and holds a position in the Sufi chronicles as high as Junayd Baghdadi (d. 910) and Bayazid Bastami (d. 874). He studied under various teachers and travelled extensively in Arabia and Syria. The Muslim scholar and Sufi Sahl al-Tustari was one of Dhul-Nun al-Misri's students. In 829 he was arrested on a charge of heresy and sent to prison in Baghdad, but after examination he was released on the caliph's orders to return to Cairo, where he died in 859; his tombstone has been preserved. Dhul-Nun's name came about in relation to an incident on a sea voyage. He was falsely accused of stealing a jewel from a merchant. He cried out "O Creator, Thou knowest best", whereupon a large number of fish