Iranshahri

Abu al-Abbas Iranshahri
Photo taken from medieval manuscript which depicts an epicyclic planetary model.
Born	9th century Nishapur (circa 9th century)
Died	9th/10th century
Ethnicity	Persian
Religion	Islam
Main interest(s)	Mathematics, Astronomy, medicine, science and philosophy
Notable work(s)	Hasti, Ketab-e jalil, Ketab-e athir,
Influenced Nasir Khusraw, Biruni, Razi

Abu al-Abbas Iranshahri (Persian: حکیم ایرانشهری‎‎) was a 9th-century Persian philosopher, mathematician, natural scientist, historian of religion, astronomer and author. According to traditional sources, he is the first figure in the wider Muslim world to be associated with philosophy after the advent of Islam.

He was born in Nishapur (modern Khorasan in Iran), the city also known as Iranshahr, hence his title Iranshahri. According to Nasir Khusraw, Iranshahri taught Rhazes and Biruni ancient Iranian philosophy.

He authored several books and treatises in Arabic and in Persian. All the books written, some of which are mentioned in passing by Biruni and Nasir Khusraw, have been lost.

He wrote three books; Jalil, Athir, and Masael u'ttabi'a, about philosophy and wisdom. Abulma'ali states that Iranshahri brought a new religion with a Persian book and named his miracle Hasti (existence). According to Biruni, he was knowledgeable about Christianity, Zoroastrianism, Manichaeism, Hinduism, and Shamanism.

According to Abu'l Ma'ali, the author of bayan al-Adyan, Iranshahri considered himself a Prophet and wrote a book in Persian which he claimed have received a divine revelation by the angel called Hasti (Existence). He believed in the unity of all religions and considered existing differences among them the results of special interests (ḡarażµ) of their followers. According to Biruni, Iranshahri had said that God took covenant from light and darkness on the days of Nowruz and Mehragan, which may reflect Zurvanite influence. According to Nasir Khusraw, Iranshahri had expressed philosophical concepts in religious terms in such books as Ketab-e jalil and Ketab-e athir, and had led people to the true religion and the understanding of monotheism.