Scholar of mathematics and astronomy (B. 996 – D. 1036, Harzem). His full name is Ebu Nasr Emir Ali b. Mansur b. Ali b. Arak. Emir Arak studied Islamic and elementary sciences in Harzem Madrasahs which had the quality of an international university at that time and from virtuous scholars who taught in these places. He became a sovereign scholar with a scientific character. He lived in Harzem during 10th and 11th centuries when elementary sciences such as mathematics, astronomy, algebra and medicine were in demand. He joined “Talebe-i Ulum’a Hayır” which mainly consisted of Turks. He gave lessons to all people who were interested in this science and who sought for his help. He raised numerous famous scholars who would remember him with good memories. One of the famous scientists he raised is the famous mathematician and algebra master Birûnî.
Emir Arak wrote around 1035 a work titled Risale el-Fihrist, which informed that this valuable Turkish scholar authored twelve books on mathematics, trigonometry, astronomy and other fields and gave their names. Without doubt, the influence of his valuable works continued for long centuries after him. In the 4th century of Hegira (9 A.D.), Ebu Nasr el-Fârabî represented the Islamic culture in philosophy; Emir Nasr b. Ârâk in mathematics and astronomy. Ali b. Arak was one of the leading mathematicians according to Cem Saraç. Besides he realized important researches with Ebû'1-Vefa el-Buzcanî about theorems concerning the proportionality of sinus in spherical triangles. He interpreted el-Macestî and Menelaos' work titled Küreviyat. Nasîru'd-Din Tusî in his book titled Şeklû'l-Kutla regarded Ali b. Arak's interpretation as a very successful work. Birûni in his Risâletü'l-Fihrist named twelve books of his master Ali b. Arak on astronomy. The influence of these books lasted for long years.
Emir Ali who had a rough life missed his homeland during his last years in Harzem. He passed away here in 1036. Mehmet Şemsettin Günaltay evaluates Emir Ali b. Arak as following:
"In 4th Century of Hegira (10. A.D.), the Islamic culture was mainly represented by three important personalities. All of them were Turks. Among them Ebu Nasr Fârâbi proved the amazing strength of Turkish genie in philosophy, wisdom, sociology and music, Emir Nasr b. Arak in mathematics and astronomy, Ebû Bekr es-Sûli in literature and history.”
REFERENCE: Mehmet Şemsettin Günaltay / İslâm Tarihinin Kaynakları (yay. haz. Yüksel Kanar (1991, s. 61), Zeki Velidi Togan / Umumi Türk Tarihine Giriş I (s. 90, 1946), Şaban Döğen / İslâm ve Matematik (s. 97, 2000), Cem Saraç / Bilim Tarihi (1983, s. 57), İhsan Işık / Ünlü Bilim Adamları (Türkiye Ünlüleri Ansiklopedisi, C. 2, 2013) - Encyclopedia of Turkey’s Famous People (2013).